[HN Gopher] An open source initiative to share and compare heat ...
___________________________________________________________________
An open source initiative to share and compare heat pump
performance data
Author : protontypes
Score : 616 points
Date : 2024-04-12 08:53 UTC (14 hours ago)
(HTM) web link (heatpumpmonitor.org)
(TXT) w3m dump (heatpumpmonitor.org)
| rq1 wrote:
| This is a great initiative!
|
| Especially now with all the integrated circuits and sensors, we
| can have a clear picture on the products if we could all share
| these data.
|
| I'm looking to get a heat pump too and was leaning towards the
| NIBE make that these data seem to validate. (They're incredibly
| silent too!)
| brabel wrote:
| I have a new NIBE pump (S735) that replaced my old, also NIBE
| (Fighter 640P) pump. It's a bit more silent than the older one
| usually, but sometimes it starts what sounds like a jet engine
| which is pretty loud. I can hear it from upstairs, far away
| from the pump, coming from the vents. I am not sure what it's
| doing when it makes that noise but it made me a bit upset with
| it, as initially I had hoped for a quieter house, and the pump
| was pretty expensive!
| henearkr wrote:
| Awesome initiative! I really appreciate it!
|
| Some (hopefully) constructive critics to make it even better:
|
| - fix the left side menu, so that, _even when the "Add fields"
| part is displayed_, it can be scrolled up and down (because right
| now if I unfold "Add fields" and further unfold some of the items
| inside it, the content becomes hidden below the bottom border of
| the screen)
|
| - add noise level information (the noise level of the
| compressor), in dB. Some manufacturers don't provide this info,
| so it would be really useful to gather it here.
| sushisource wrote:
| Noise level seems huge. I don't have one, but every place I've
| stayed that has one the noise they make drives me insane. I
| would be really trepidatious about installing one in my place
| for this reason.
| RedShift1 wrote:
| A world map and efficiency/consumption would be nice, so we can
| see where in the world heat pumps are most effective.
| akira2501 wrote:
| > so we can see where in the world heat pumps are most
| effective.
|
| They're not efficient when the temperature drops below a
| certain point. This is predictable and based on system design
| criteria. It doesn't mean it's not effective, it's just that it
| wouldn't be a reliable source of heating year round. It may
| still make a worthwhile addition to another system, or combined
| with several other upgrades, may become an acceptable single
| solution.
| brnt wrote:
| Reliable and efficient are different things.
|
| A solution that is inefficient two week a year but efficient
| the rest can still be cheaper than some hybrid setup.
|
| If it is expected it simply won't work a few weeks a year,
| sure, that's clearly not effective.
| akira2501 wrote:
| You've summed my points exactly while missing the major
| one. You don't need monitoring to determine any of this.
| You can just look at the construction of the building and
| the weather charts and you're done with the "will a heat
| pump be effective?" question.
| sokoloff wrote:
| Sort of. My house is 100 years old and was built without
| insulation (some rooms were insulated through remodels
| over the years). It uses water circulation and cast iron
| radiators and stays comfortable with my ancient cast iron
| boiler and 180degF water.
|
| To know whether a heat pump (air-to-water) can replace
| that boiler effectively and maintain comfort, I had to
| find out whether the house would be comfortable with
| water temps of 135degF or so. Is there an amount of
| "that's just looking at the building construction" to
| make that analysis? I think maybe technically yes, but
| practically no.
|
| As it was, to get an answer, I abused my old boiler by
| turning the water temps down (causing condensation and
| slow damage [planning to replace it anyway]) and seeing
| what happened on cold days.
| wenebego wrote:
| You didnt need to do that, though. It peobably wouldve
| been easier to use manual j (or some software) to
| estimate the heat loads in the house, with given set
| points, using weather station data.
| sokoloff wrote:
| I can find/closely estimate the _heat loss_ easily. What
| is much harder to find is the heat gain /transfer into
| the room from 1920s cast iron radiators at 135degF flow
| and the balance of the system flow temperatures at those
| 45degF lower flow temps than originally designed.
|
| Then, because the answer is almost always going to be
| "yeah, it's going to be really close...", I felt well-
| advised to prove it via experimentation rather than
| commit to changing the heating plant to a system that
| could not provide 150degF flow temperature.
| rainbowzootsuit wrote:
| If you are ok with IP units the formula is 500 * GPM *
| delta-T for water as the fluid.
| sokoloff wrote:
| The question is not about the general hydronic heating
| formula [nor manual J heat loss estimations], but rather
| "what will the delta T of the rad in this particular
| room, in this piping network [it's a converted gravity
| feed system, now being a pumped], using 69degF room temp
| and 135degF leaving water temp from the heat source?"
| brnt wrote:
| For the, for lack of a better word, standard radiators
| there is a formula with a dT^4. But I totally agree, this
| isnt all that straighforward, given that for the dozons
| of installers, experts and home owners I have spoken, Ive
| heard dozens+1 methods for estimating. Estimating heat
| loss from a given building and estimating power output of
| a given installation of radiators, very few people seem
| to be able to calculate that.
|
| If your heater can go low (mine bottoms out at 50
| unfortunately), by far the easiest is to just test.
| rainbowzootsuit wrote:
| This is going to be a complex problem because of the
| shape of the radiator and you'll need to calculate
| radiative and convective components of heat transfer i.e.
| you'll need finite element analysis to do this. If you
| simplify it to a simple shape like a rod or slab you can
| get somewhere in a calculation, but this is only going to
| give an instantaneous measure because of heat transfer to
| the rest of the universe.
|
| Alternately, to get a realistic measure, you'll need to
| set your boundary conditions about what the heat flow out
| of the room will be, which is a bit simpler to setup with
| U-values, area, delta-T, and heat capacity of materials.
| You'll also need to do this to every other room in the
| building simultaneously. This is a Manual J, or heat
| balance method or the radiant time series method load
| calculation that will balance out with the amount of heat
| leaving your radiator without knowing its specific shape.
| ClumsyPilot wrote:
| Don't you want to replace the radiators with large
| vertical floor to ceiling radiators to get the same
| amount of heat transfer at a lowest possible temperature?
|
| I am not familiar with the nuances, but this appears to
| be an equation with two variables - water temperature and
| radiator surface area. Maximising surface area should
| slow you to use lower water temperature. And the lower
| the water temperature, the more efficient the heat pump
| will be?
| sokoloff wrote:
| As a mechanical engineer, would I like to do that?
| Absolutely!
|
| As a homeowner who bought a 1920s house because I like
| the character of a 1920s house, would I like to do that?
| Absolutely not!
| hojdra wrote:
| What was the answer you came to? I'm in a very similar
| situation
| sokoloff wrote:
| Ref: https://news.ycombinator.com/item?id=39144329
|
| A two-part answer:
|
| From the Mechanical Engineering/Thermodynamic angle:
|
| > Ultimately, I proved to myself that a heat pump could
| work down to an outside air temp of about 18degF [which
| is slightly above our 99th percentile design temp] with
| flow temps of 135degF, so an air source heat pump could
| work with slightly reduced comfort on about 2% of days or
| could work all the time with supplementation with a 9kW
| [30K BTU/hr] electric boiler.
|
| From the commercial angle:
|
| > What killed the project is no heat pump installer was
| interested in doing the work (as reflected by outright
| declining to bid, while bidding a 4-hour gas boiler swap,
| or by bidding so high that they might as well not have
| bid, while also cheerfully bidding a 4-hour gas boiler
| swap). So my house still burns gas for heat.
|
| On the engineering front: I think the answer is often
| going to "<hissing inhale> It's going to be close; we
| should probably test it..."
| hojdra wrote:
| Thanks for the response. My feeling is that maybe in
| about 10 years Air-to-water Heat pumps will be more
| common in the US and we might have a better chance of
| getting a reasonable installation quote
| brnt wrote:
| Yeah no. It's become a bit of a hobby of mine, heatpumps.
| If I ask 5 experts/installers to take a look at a
| building I'll get 6 estimates, varying wildly. Plus,
| installers are still consistently over dimensioning and
| thus killing your sCOP, because they don't want customers
| to complain 'its slow to heat' and so on.
|
| Calculating the heat loss of a house is really not
| trivial. Often you'll have no idea of the materials used
| or the quality of installation, and not really a way of
| finding out unless your up for some destructive
| investigation.
| KeplerBoy wrote:
| Heat pumps are reliable even in unfavorable conditions.
|
| You will have to invest a lot more electrical energy and you
| might not be pumping heat as much as just converting
| electrical energy to heat, but let's not spread the myth that
| a heat pump will leave you freezing once outside temperatures
| drops below a certain threshold.
| akira2501 wrote:
| A heat pump without a resistive heating /option/ will
| absolutely cease working below a certain temperature. They
| do, for whatever reason, sell systems that way in some
| regions.
| KeplerBoy wrote:
| That's true. Strictly speaking a heat pump doesn't need a
| resistive heating element, but I've never heard of units
| not containing that feature. After all it's dirt cheap
| and enables the reliability, we're discussing here.
| jwr wrote:
| Perhaps, instead of spreading FUD, it would be worthwhile
| to mention these "certain temperatures", so that people
| can make an educated decision of whether it applies to
| them at all.
|
| I'm looking at the datasheet for my Fujitsu system and it
| is specified to work down to -25degC.
|
| Does it lose efficiency when it's cold outside? Sure. But
| guess what, it's still more effective than resistive
| heating! I am starting from a SCOP of 4.89.
| bluGill wrote:
| The UNIT is specified to work down to -25. The SYSTEM
| includes the building it is installed in: the local
| climate, the size and heat loss of the building, how the
| install was done, and likely some other factors I'm not
| aware of. If you get less heat from the unit than you
| lose via other means the system isn't working even though
| it is delivering heat.
| akira2501 wrote:
| Perhaps you should have read my comments more carefully.
| There is absolutely zero "FUD" in any of them. I'm just
| pointing out facts. The primary fact is that you don't
| need historical data from heat pump installations to know
| if they'll be efficient in a given area or not.
|
| They're devices. They're engineered. They have
| specifications. The specifications have implications as
| to how they will function in a given environment.
|
| I'm not here to sell heat pumps or to make you feel good
| about your past purchases. Are you?
| egberts1 wrote:
| Real question is does it prevent freezing? Like 100%.
| After all, the human body is quite resilient ... above
| freezing.
|
| I am thinking in Nome, Alaska where such heat pump could
| prove its versatility as an anti-freezing component of
| living quarters or even maintenance shed.
| bluGill wrote:
| Humans can put on clothing and be fine in very cold
| temperatures. However pipes cannot 1C is a hard minimum
| safe temperature, once it gets colder than that you risk
| pipes breaking.
| bluGill wrote:
| > let's not spread the myth that a heat pump will leave you
| freezing once outside temperatures drops below a certain
| threshold.
|
| That is not a myth - I have a heatpump in my house and it
| will leave me freezing on the coldest days. The system is
| sized so that it cannot keep my house warm at -5C (the
| system can deliver heat, but the house will cool down).
| Worse, it did get below -25C here for a couple days which
| is as cold as any heat pump will work - I don't know of any
| house that is insulated so well as to be warm when the
| outside temperature is below -25C for a few days without
| some heat - but mine isn't one.
|
| A correctly sized heat pump can keep your house warm to
| -25C, but if the installer doesn't give you a correctly
| sized system it will not. Most installers don't know how to
| size heat pumps.
| HPsquared wrote:
| Ground source heat pumps don't have the icing problem. More
| expensive to install, though.
| ClumsyPilot wrote:
| I think this could be Resolved by scale, but that's
| precisely what the west is really bad at
|
| If we standardised ground source heat pumps as a must have
| all multi dwelling developments like apartment blocks and
| rows of terraced houses who could share one well et cetera,
| It would not be a noticeable cost at all
| bluGill wrote:
| Maybe, where are live there isn't much ground water and
| so no well can deliver enough water to be useful for a
| large building HVAC needs. There are a lot of ground
| source heat pumps around me, but they are all the coil in
| the ground style which doesn't scale the same way and so
| will be a lot more expensive to install.
| carnot wrote:
| Certified performance rating data from virtually any air-to-air,
| air-to-water, etc., system sold in North America is available
| here [1]. This includes capacity, COP, and sound data. It also
| includes integrated performance rating metrics like SEER, HSPF,
| IEER, etc.
|
| [1] https://www.ahridirectory.org
| sokoloff wrote:
| As-engineered and as-installed/configured figures have the
| potential for a wide spread. Both are useful, but as a
| homeowner, I'm interested in seeing my as-installed figures
| more than the manufacturer or test lab's figures.
|
| As a shopper, I'd want to see a nearby house's figures as-
| installed by my prospective contractor.
| Haemm0r wrote:
| A big factor for the total energy consumption besides the
| heatpump is the rest of the heating system. For our house the
| yearly energy consumption of the heatpump is around 1.4MWh/y
| (for floor heating, warm water and cooling of the bedrooms in
| summer;this number is reported by the heatpump control
| system) but the hole heating system including all the pumps
| and so on is 2,55MWh/y.
| rainbowzootsuit wrote:
| It's important to note that those ratings are all tested under
| specific conditions that includes a rather short (~3m IIRC)
| lineset and other parameters of installation that in the field
| can lower the capacity as more energy goes to the pumping of
| the liquid refrigerant. Particularly the lineset length.
|
| Also, the testing varies between "traditional style heat pump"
| and inverter driven "VRF" equipment.
|
| That's not to say that the AHRI information isn't useful, but
| the numbers can be a little subtle to get to an apples to
| apples comparison and you should have a selection done based
| upon some real estimated line lengths and installation
| conditions.
| phkahler wrote:
| Isn't the "crowd sourced"? It's not open source.
| protontypes wrote:
| Here the repo with the open source license:
| https://github.com/openenergymonitor/heatpumpmonitor.org
| tikkabhuna wrote:
| Is that just the website? Is there a way to export the raw
| data?
| wanderingmind wrote:
| +1 yes we need a way to export and analyze data to get the
| insights we want. Would be great if we can share through
| Datasette which is tailor made for such applications
| naraic0o wrote:
| there's an export button at the bottom of the table which
| copies a CSV to your clipboard.
| phkahler wrote:
| The heatpump performance data looks crowd sourced. If the
| website and DB are run with open source software, that's a
| different thing and seems secondary.
| meigwilym wrote:
| Great to see a local project at the top of HN! Good work guys.
| Faaak wrote:
| Heat pumps _are_ amazing! The power of physics at play: spend 1
| unit of energy to gain 4.
|
| Some naysayers will say that it doesn't work the 3 days of the
| year where it's -15degC outside, without talking about the other
| 100+ days where it's not that cold and where the heat pump is
| amazing.
|
| Disclaimer: I self installed one for my house (13kWth) and I'm
| very glad I did
| gjm11 wrote:
| In fairness, the days when it's -15degC outside are exactly the
| days when you _really want your heating to work well_...
| derkoe wrote:
| Most heat pumps fall back to electric heating when it's too
| cold. So, on these few days you will need the same amount of
| electricity a typical electric heating will need.
| tomohawk wrote:
| which spikes the electricity demand from the grid and puts
| it under the most strain when its most critical for the
| grid to stay up, which means the grid has to be
| overdesigned, which means that the air based heat pumps are
| a poor choice for a reliable grid.
| yurishimo wrote:
| It depends on where you are. In many places worldwide,
| extreme cold is also generally quite clear from clouds
| unless you're literally in a storm, in which case, the
| high winds are just as likely to cause problems. Rooftop
| solar should be more than enough to offset your own
| usage.
| bluGill wrote:
| In nearly all places extreme code means dark! Sure there
| are less clouds, but the latitude is high and so there
| are not only few hours of daylight, the earth's angle is
| also working against solar.
| rssoconnor wrote:
| The demand comes at the coldest part of the day, which is
| typically overnight, which is far off peek demand times.
| sanderjd wrote:
| I don't think this conclusion follows. It is true that
| variability is a challenge for grids, but it is not clear
| that it is better to trade more total energy usage (per
| useful unit of work) for less variability. Variability is
| certainly a challenge, but not an insurmountable one, and
| also one that must be faced regardless nearly everywhere,
| as solar power has become too cost-effective to be
| ignored.
| jtbayly wrote:
| Isn't electricity demand always going to be highest on
| the coldest days?
| beejiu wrote:
| The UK is rolling out smart meters to every property. In
| the past 2 winters (following on the Russian gas crisis),
| they have run programs that pay PS3 per kWh reduced
| demand. This is a nice way to balance the grid during
| extreme demand.
| michaelt wrote:
| _> programs that pay PS3 per kWh reduced demand._
|
| That much? How do I get in on that?
|
| My energy supplier's demand reduction scheme only pays
| PS10/month total.
| astiela wrote:
| octopus energy seems to be the best for energy i have
| seen so far in the uk alongside their smart tariffs
| https://share.octopus.energy/umber-squid-619
| beejiu wrote:
| It's called the National Grid ESO scheme and you sign up
| through your supplier when it's open. However, some
| suppliers take a cut of the ESO payment. Alternatively,
| you can sign up to Uswitch Utrack
| (https://www.uswitch.com/mobile-app/), which passes 100%
| onto the customer. (Disclaimer: I used to work at
| Uswitch.)
| thehappypm wrote:
| This is untrue. Mitsubishi hyper heat units do not have
| this feature, and they're the gold standard. I wish they
| did, though
| sokoloff wrote:
| Hyper Heat is a tech that is on multiple different models
| of Mitsubishi. All of the SVZ (ducted air handlers
| attachable to Hyper Heat or H2i mini-splits) do support
| (optional) electric resistance heater kits.
| thehappypm wrote:
| That's correct, air handlers for ducted systems can
| absolutely have heat strips. That's actually pretty
| standard. I have never seen one for a mini split though
| -- can you share a link?
| sokoloff wrote:
| https://ces.mitsubishielectric.com/wp-
| content/themes/melco/a... documents the SVZ indoor unit's
| ability to have electric resistance heat and be connected
| to Hyper Heat SUZ outdoor units.
|
| Whether you call that mini-split or not is up to you, but
| it's definitely a heat pump system that is Hyper Heat and
| supplemental electric heat capable, and getting down to
| one-ton units seems "mini" to me.
|
| Mini-split means "smaller than conventional system
| ["mini"], condensor and evaporator are connected by long
| refrigerant lines ["split"]". It doesn't necessarily mean
| "wall/floor/ceiling indoor unit that has no ducts",
| though a "ductless mini-split" is the most common
| configuration of mini-split (because of the cheapness and
| ease of installation).
| https://zeroenergyproject.com/2022/03/09/what-is-a-mini-
| spli...
| magicalhippo wrote:
| We have a air-to-air heat pump (minisplit). We also have heat
| foil in the floors. We've had weeks around -20C and below
| most winters.
|
| I do hear the minisplit working hard those weeks, but we just
| needed a bit of extra help from the floor heating to have a
| comfortable 20C indoor.
| Mountain_Skies wrote:
| Depends on how many of those days there are. If it's only
| half a dozen or so, I can deal with putting on an extra layer
| of clothing in the house for a handful of days per year. As
| long as it's warm enough inside to prevent damage like pipes
| freezing, a small amount of personal discomfort for a few
| days is acceptable.
| turtlebits wrote:
| Get a few space heaters, they're cheap.
|
| Many new homes that are heat pump only will also require some
| sort of resistive heating as a backup.
| wernerb wrote:
| This needs far more attention. Combi boiler installers tend to
| massively oversize the CV. But with heat-pumps you need to be
| far more accurate. And it does not make sense to design for a
| temperature that occurs only a couple of days in the year. You
| can just have the backup heater kick in which is far more
| efficient for a couple of days than having a heavier heatpump
| for the rest of the year that can not modulate back as much as
| a smaller heatpump.
| stilley2 wrote:
| I recommend this technology connections video which dives
| into this in wonderful detail
| https://youtu.be/DTsQjiPlksA?si=gx18FGOcjsv5PpNg
| rssoconnor wrote:
| > than having a heavier heatpump for the rest of the year
| that can not modulate back as much as a smaller heatpump.
|
| Aren't basically all modern heatpump variable speed, and thus
| can modulate back?
|
| That said, I totally agree with your overall point about
| right-sizing your heat pump, but it is more about saving
| money on the unit rather than worrying about cycle times.
| bluGill wrote:
| Modern heatpumps can modulate, though it isn't 100%. I
| recommend people consider two smaller heat pumps in many
| cases - it costs more upfront but can modulate down more
| and if one system breaks the other can handle everything
| most days of the year (some rooms will be a bit
| uncomfortable)
| verelo wrote:
| So, i have a house in Haliburton Ontario. Historically we drop
| a cool $3k a year on propane.
|
| Last year we installed a Mitsubishi hyper heat ductless system.
|
| We used zero gas this year. Read it again, zero.
|
| It's lakefront, very remote, and the largest electricity bill i
| got was around $450 for a month and then they dropped back to
| something more like $250. The savings are huge, I'm no longer
| stressed about running out of gas...and the heat pump performed
| well beyond its advertised specifications. We had a few -25C
| days and it was humming hard, but the house stayed a
| comfortable 20C inside. The house is around 3000sqft and we
| didn't even get the largest unit, i can't stress enough that
| they actually operate better than advertised.
|
| We would run a fire from time to time but we did that with
| propane too, it's mostly ornamental.
|
| https://photos.app.goo.gl/FCwLJQAtoG67g9y86
|
| https://photos.app.goo.gl/TwiMaSAj9hGxYqby6
|
| https://photos.app.goo.gl/gYVYvVEB3whLCv1dA
|
| https://photos.app.goo.gl/49RcBdBuUZ2jVN3J7
| Siecje wrote:
| That's a lot of lines going to the outdoor unit.
|
| Is there two per indoor head?
| matthiaswh wrote:
| It looks like that unit may have 3 indoor heads. Two lines
| per head. Power to each head. Power to the outdoor unit.
| bluGill wrote:
| Looks like it. I'd suggest anyone looking at a system
| like that install at least 2 separate outdoor units. That
| way if one breaks the other can still work - and most of
| the year it will be powerful enough to handle the whole
| house (some rooms will be a little uncomfortable but
| bearable)
| verelo wrote:
| This is correct, 3 heads. One on each level of the house.
| jefftk wrote:
| It's worth running the numbers based on your particular
| utility costs, though. In our case, with somewhat expensive
| gas and very expensive electricity, the heat pump would have
| cost quite a bit more to run:
| https://www.jefftk.com/p/running-the-numbers-on-a-heat-pump
| stephen_g wrote:
| With an air-to-water system like a Vaillant aroTHERM plus
| you could possibly achieve your break-even COP of 4.5 (the
| 12kW unit costs about US$7,200 in Europe, although from
| what I hear about the US heat pump market you'd probably
| pay like $20K for the unit alone for some reason).
|
| (Also, how do you guys function with those strange units?
| Therms, BTU/hr, etc. - all so confusing. Surely
| electrification and the shift to heat pumps could be a
| convenient excuse to start using watts (kW in this
| magnitude) for heat and joules (usually MJ) for gas!)
| jefftk wrote:
| I do think an air-to-water could make sense for us,
| though it wouldn't be able to handle the coldest days
| because our radiators aren't sized to keep the house warm
| at the lower water temperatures it puts out. The main
| problem is figuring out who can install one, since it's a
| pretty unusual product here.
|
| (You get used to whatever units you're using, and the US
| units make some calculations easier and others harder. If
| I could switch it all over to the SI system without
| massive transition costs I would, though!)
| sokoloff wrote:
| You might be surprised at how well cast iron rads can
| provide comfort at low outside air temps and low flow
| temps. (I'm in neighboring Cambridge in an old,
| poorly/non-insulated house.)
|
| https://news.ycombinator.com/item?id=39144329 has a bit
| of details on the experiment I ran back in 2022 to prove
| 135degF flow would work for us. (If you have a condensing
| boiler, you can run this experiment safely; if you have a
| non-condensing boiler, you can run it, but not for very
| long as you'll be damaging the flue and boiler with
| condensation at these lower temps.)
|
| My outdoor reset curve (sadly, on a gas combi boiler
| because of the "pretty unusual product" factors) is now
| set to 105degF at 55degF OAT and 154degF at 0degF OAT
| (which is lower than the design temperature here, but it
| gave me more resolution to tweak the line to fit the loss
| just right; it's spot-on on the lower end, with the
| system running 22-24 hours per day when it's cold out and
| stays that way up until around freezing, where the
| utilization falls off).
|
| Matching the gain to the loss quite closely has resulted
| in a house that's the most comfortable since we moved in
| in 2007 and gas bills with the combi went down about 46%
| (versus a 1990s oil-to-gas conversion of a 1950s boiler,
| so not a realistic comparison for anything that wasn't
| built by General Motors [not a typo]).
| jefftk wrote:
| We have one loop with cast iron radiators, but the other
| two loops are modern baseboard. When we installed a
| condensing boiler in 2015 I needed to adjust the outdoor
| reset curve up so the loop that serves the first floor
| wouldn't leave it under temp on cold days.
|
| Even our cast iron radiators are smaller than you might
| expect for the age of the house, because they were
| designed for water above its normal boiling point (using
| mercury pressure: https://www.jefftk.com/p/mercury-
| spill).
| sokoloff wrote:
| I also have one loop of modern baseboard. Fortunately,
| it's in the attic conversion where they did insulate the
| rafters while doing the conversion, so it works even at
| that lower temp. I did do something slightly
| unconventional in plumbing that zone in a
| primary/secondary and it gets the water from the boiler
| "first" and returns it to the primary loop ahead of the
| main zone which is all cast iron rads. That means the
| baseboard gets the hottest water possible and the full
| potential flow from the boiler if it "needs" it. In
| practice, that zone tends to only run 4-5 hours per day
| while the main zone is running 22-24 hours, so either
| what I did works _really well_ and /or I didn't need to
| do it in the first place.
|
| But, you've already discovered your reset curve with
| modern equipment, so you know the right answer for your
| place.
|
| Thanks for the story on mercury pressurization!
| Fascinating. I learned a lot about our old house
| (originally gravity circulated as well, but near as I can
| tell, pressurized only to the typical 12-15 psi and with
| an in-ceiling green steel expansion tank:
| https://structuretech.com/wp-content/uploads/2020/03/Old-
| sch... )
|
| (And of course, sorry to hear about your contamination
| inconvenience and expense!)
| boringg wrote:
| Jefftk I'm in the same boat -- what I'm going to have to
| do if I want to do the air to water heating is bring in a
| booster/combo unit that will boost the water temp to make
| the house the right temp. So I'm still tied to gas but
| much lower amounts - heat pump does the majority of the
| work and I still have protection on very low temp days.
| jefftk wrote:
| Hmm. I wonder if adding an air-to-water pump to the
| existing loop, before the boiler, can be made to work?
| Perhaps with a microcontroller intermediating the
| thermostats on both to turn each on at the ideal time?
| davidw wrote:
| We got a heat pump installed alongside the gas system,
| since it's still working.
|
| I would love it if there were a service or some code to
| look at 1) gas prices 2) electricity prices 3) how
| efficient the two systems are and switch back and forth
| depending. Like... if it's -10C out, run the gas. As it
| gets closer to 0C, switch over at some point.
|
| If gas is flat out always cheaper, you could still put a
| cutoff point where you're willing to spend a bit more
| because it's better for the environment.
| verelo wrote:
| Depends where you are. Gas is certainly not cheaper for
| us. I did the math based on cost per KWH of fuel consumed
| v's the efficiency of the unit producing it. Natural gas
| would be slightly more expensive (marginal though...2% or
| so) but propane is around 3x more expensive, and with
| many people on oil the math is even worse.
|
| In many regions electricity isn't as cheap as ours
| though, so that changes the game.
| davidw wrote:
| Right - it feels like a pretty dynamic calculation and
| it'd be cool if there were a service to do it for you.
| verelo wrote:
| The number of times I've almost started making that
| service...maybe when I get a free moment, I really want
| it to exist too.
| verelo wrote:
| 100% agree. Our electricity costs are fairly low, and its a
| very low carbon source (mostly hydro electric + nuclear),
| so for us it makes a huge amount of sense. If you're in
| Alberta, where most of the electricity comes from
| coal...theres no logic in switching to electricity.
|
| I'd argue that's politically motivated and very deliberate
| however...
| stormbrew wrote:
| Almost all coal plants in Alberta have been shut down and
| it's a small minority of net generation now. Natural gas
| has taken up most of the slack, but there's actually
| quite a lot of solar and wind generation in Alberta
| considering the politics (though that's likely to slow
| down now).
|
| http://ets.aeso.ca/ets_web/ip/Market/Reports/CSDReportSer
| vle...
| verelo wrote:
| Ah i didn't realize the coal plants were retired! That's
| good to see. I was looking at the carbon impact per kwh
| in Alberta earlier in the year for a project I was
| working on, and was surprised how high it was. I guess
| other areas of the country just have a lot of other
| sources diluting the impact.
| fnbr wrote:
| Yeah Alberta has very little hydro, while
| Ontario/Quebec/BC have lots, so our electricity generates
| a lot more carbon.
| itsoktocry wrote:
| > _Historically we drop a cool $3k a year on propane._
|
| Similar to our situation, also in Canada; we cut our fuel
| bill by 3/4 after getting a heat pump. I still run the
| furnace on the coldest days, because it's hard to beat. But 9
| days out of 10 the heat pump is all we need. The fact that it
| doubles as an AC unit (and is even more efficient) is gravy.
|
| I also bought a heat pump hot water tank, and so far so good.
| sentrysapper wrote:
| Can I ask what model did you get and what part of Canada
| are you in?
|
| More to the point, I'm looking for a recommendation for a
| smaller unit to heat 750 sq ft. in Quebec.
| verelo wrote:
| Yeah! The AC bonus is amazing. The summer gets so sticky,
| not anymore. We got it in around July I think, made for an
| amazingly comfortable August.
| bregma wrote:
| I live a few 100 km east of there and just had a heat pump
| installed last fall. I still have to spend $800 a year on
| wood but now my home is 20 C all day every day and I no
| longer have to break the ice on the dog's water bowl in the
| mornings. I still fire up the stoves to keep hydro costs down
| and so far the hydro bills haven't been particularly
| different from previous years when I had to use supplementary
| electric resistive heat. Then again, it's been a particularly
| mild winter with zero days below -30.
|
| I had a Moovair with three heads installed.
| verelo wrote:
| This winter was really mild. I was curious if we'd spend
| more or less, and honestly i wasn't super concerned. My
| napkin math suggested it would be comparable, but come with
| the benefit of reducing the risk we'd run out of gas. The
| propane truck cant make it up our road from late November
| early April, and last year we got down to around 20%
| remaining (which is around the point where the tank stops
| working due to there not being enough pressure).
|
| Huge bonus that its been cheaper, and substantially...but I
| just love relaxing about the reduced risk of the house
| running out of fuel.
| boringg wrote:
| Did you consider putting up solar to counteract the
| additional electrical load? Sure it would take 7-10 years to
| pay off the solar asset but after that its free electricity
| and heating. Something I'm playing with but its a bit more
| difficult in the city.
| thechao wrote:
| > Disclaimer: I self installed one for my house (13kWth) and
| I'm very glad I did
|
| My HVAC guy keeps telling me to install a couple of heat pumps
| (he doesn't like driving out to me), solar panels, and an in-
| house battery; what sort of complexity was this job? Are there
| online sources you used?
| matthiaswh wrote:
| Installing heat pumps doesn't require a ton of domain
| knowledge (assuming you're already a handy person), but it's
| a lot of work. It took 3 guys who do it for a living 160+ man
| hours to install our mini-splits. They had to drill through
| walls, attach channels to the siding, crawl into a tight
| crawlspace, do some plumbing when they hit a water pipe with
| their drill, wire up electrical, and add breakers to the
| panel.
|
| The only thing that might catch you up is designing the
| system and ensuring you right size it for your heat load
| requirements. I'm sure you could research this pretty well,
| but your HVAC guy might also be happy to consult on that
| portion.
| turtlebits wrote:
| If you have a good spot (ie exterior wall), installing a
| mini split can be an easy DIY. It probably took me a max of
| 6 hours to do it all.
| sumtechguy wrote:
| With this sort of work let the HVAC guys do the research for
| you. Call 3 of them get quotes. Then research what they are
| offering. Pick the one you like. Last time I did this around
| 2008 it was about 5k-15k I was quoted. I asked all 3 for a
| small, medium and large systems. For me it was mostly an in
| place replacement. The ducts were already there. The
| refrigerant lines were all ready in place. The biggest cost
| was the unit themselves and some change out of the
| controllers. The labor was about 1 days worth of work for 4
| guys.
|
| You can also gain quite a bit by just fixing drafts and
| putting in proper insulation. Which can be much cheaper to
| do. I also had the guys go thru and fix an leaks in the duct
| system. That way the air was coming out where it should. It
| is amazing how badly that is installed many times. I also had
| them put in an attic fan which vented the attic when it got
| to about 110F. Insulation would have helped more there and I
| screwed up and put it off. If your house is older than 2000.
| I say go thru and review the existing insulation and look for
| drafts first.
|
| It trimmed my bill from about 350 a month to 200. My new
| house has excellent insulation the house is slightly bigger
| and the power bill is in the 80-150 range (less because I got
| solar, but I figured out the actual cost anyway). It has one
| unit and an air valve to switch between the floors. So the
| total cost is lower but the one unit will run longer. That
| savings I am getting is mostly because of better insulation.
| corbet wrote:
| -18degF here (-28degC) here this winter. The heat pump
| (Mitsubishi) definitely worked hard and burned through our net-
| metering credit, but it did what we needed it to do. -15degC is
| just not even remotely a problem.
| dghughes wrote:
| >Some naysayers will say that it doesn't work the 3 days of the
| year where it's -15degC outside,
|
| That used to be true but modern air-source heat pumps are
| better. But even so the efficiency drops it's just physics.
| Even if a heat pump can grab heat at -15C it will need to run
| longer when it's very cold, reducing lifespan of the unit. At
| some point it will just switch over to pure electric so your
| power to heat 1:4 is now 1:1.
|
| Ground source heat pumps are far better and even more efficient
| that air source but quite expensive to install.
| switch007 wrote:
| Just to be clear, it works perfectly at -14c and above? Or is
| there some disappointing performance in an intermediate range?
|
| I'm in Northern England and it's not uncommon for weeks of -5c
| to 5c in winter, some snowy days, plus serious damp making it
| feel even colder. So I'm curious if a similar system would be
| similarly amazing here.
|
| I've read many people say they work perfectly because it won't
| hit -20c (a nice Strawman...)
| oakesm9 wrote:
| A lot of these are UK based systems which are installed by
| installers with Heat Geek[0] training.
|
| They're an interesting company who's trying to fill in the lack
| of training that traditional gas heating installers have to
| properly install air-to-water heat pumps in the UK. They also do
| homeowner training courses and a guarantee scheme on their
| certified installers (they'll fix the system for free if the SCOP
| is below a designed level).
|
| They did a series of videos with Skill Builder[1] (who's a bit of
| a heat pump sceptic) where they fixed a badly installed heat pump
| that was causing a lot of issues. That install is currently 7th
| on the linked website[2] with a SCOP of 4.5 (450% efficient).
| Obviously a bit of a sale pitch from them, but there's loads of
| interesting information about WHY they're making the changes that
| they are.
|
| [0] https://www.heatgeek.com
|
| [1] https://www.youtube.com/watch?v=BesfqnHPxLU
|
| [2] https://heatpumpmonitor.org/system/view?id=196
| naraic0o wrote:
| it's funny actually, i've been binging their videos the past
| few weeks, since i'm looking into buying a home in need of
| renovation, and was happy to see their logos as part of one of
| the default columns.
|
| they claim also to be mainly motivated by the climate crisis
| and are even, now, developing an open source water heater,
| which... you don't often hear about in industries such as home
| appliances or heating:
| https://www.youtube.com/watch?v=uFBbArwAXS8
|
| i'd love to install an air-to-water heatpump myself, but i'm
| untrained and i guess i'm feeling a bit of the dunning-kruger
| effect while learning from the heat geek videos.
| stavros wrote:
| What's Skill Builder's skepticism based on? Don't heat pumps
| deliver on their promises?
| stephen_g wrote:
| Heat pumps require some domain-specific knowledge to build a
| system that costs less than gas for the same building (the
| crossover point is near a seasonal average COP of 4.0 at UK's
| gas and electricity prices, as mentioned in other comments
| SCOPs of 4.5 are very possible). Yet there are subsidies
| available and installers without the knowledge (who would
| normally be installing gas systems) are installing them
| basically without sizing radiators correctly or by doing
| things that reduce performance (big buffer tanks, lots of
| zoning, extra pumps that are unnecessary, etc.).
|
| So there are lots of horror stories of companies installing
| systems that don't work very well and cost a lot of money to
| run, which makes people think heat pumps are crap. But
| usually people like Heat Geek trained installers can fix such
| systems without changing the equipment - often both providing
| more comfort than gas (less thermal cycling because heat
| pumps with inverters can modulate their output more precisely
| instead of hard switching on and off) and costing less to run
| than gas.
| stavros wrote:
| I see, thanks. This provides a counterpoint to the sibling
| comment of "they don't perform but everyone blames the user
| for doing it wrong", but also sounds true, so hopefully as
| installers learn more about how to correctly install heat
| pumps, they'll perform better.
| darkwater wrote:
| What do COP and SCOP acronyms mean in this context?
| stephen_g wrote:
| COP is Coefficient Of Performance, basically the heat
| they produce divided by the electricity input, so a COP
| of 4.5 means that 1kW of electricity produces 4.5 kW of
| heat (it's taking heat from the environment so you can
| say a COP of 4.5 means it's running at 450% efficiency,
| but that's only in terms of electricity use, not actual
| overall efficiency - but electricity use is what we care
| about).
|
| COP is only an instantaneous measurement though, and
| changes depending on the outside temperature. So if you
| need heating for five months a year, and it's usually
| exceeding COP of 5 for 80% of that time but dips down to
| a COP of 3.0 on the three or four coldest days of the
| year, it's not really correct to say it's either >5 or
| that it's 3.0 - so SCOP is used as a 'seasonal' COP that
| is averaged over a longer time period, so you can compare
| different systems over the longer term.
| rainbowzootsuit wrote:
| COP (coefficient of performance) is taken at a full load
| condition with specific indoor/outdoor conditions.
|
| SCOP (seasonal coefficient of performance) is a weighted
| average of performance at different load conditions that
| represent different outdoor conditions based upon an
| average binning of weather conditions.
| switch007 wrote:
| Most if not all energy/green subsidy schemes in the UK in
| the past couple of decades resulted in tons of cowboys
| rushing after the gold, and doing a terrible job and even
| causing serious long-term damage to the property.
|
| No different this time round I imagine.
|
| It's so infuriating - literally handing money to conmen
| beanjuiceII wrote:
| No they don't and it's kind of like agile everyone tells you
| it's not done the right way otherwise it would work. But when
| is sold it's sold as is it's great.. Very deceiving for
| customers
| bluGill wrote:
| Maybe. However a heatpump sized to cool your house in summer
| cannot heat your house when the temperature is below about
| -3C. The heatpump might be able to produce heat to -25C, but
| it is too small to produce enough. Thus my system (in the US)
| that I just paid a lot of $$$ to install last fall leaves me
| using the backup gas heat a lot more than I wanted last
| winter which is disappointing. (It did get below -25C last
| winter for 2 days so I'd need that backup heat anyway, but I
| was expecting only 2 days not most of a month)
| stavros wrote:
| Hmm, that's interesting, we have fairly large temperature
| swings (typically -15 C in the winter to 40 C in the
| summer), so it'd be interesting to see if the heat pump
| could replace the AC unit and the gas heating.
| Glyptodon wrote:
| They work okay in my area for -1C to 46C, imagine for
| your range maybe you just get a model that has improved
| heating over a basic one, whether that means ground
| source, more stages, or a heating element.
| glxxyz wrote:
| I'm in a similar zone and replaced (delivered) propane
| with a ground source heat pump 2 years ago. Constant
| temperature indoors (3C warmer in summer than winter)
| with plenty of AC capacity to spare. Breakeven is about 5
| or 6 years.
| newZWhoDis wrote:
| What are the following specs for your unit?
|
| SEER2
|
| HSPF
|
| BTU
|
| Feel free to post the model #'s as well.
| rainbowzootsuit wrote:
| A properly sized system will be based upon the worst of the
| heating or cooling conditions.
|
| Luckily an inverter heat pump can run down to about 25%
| full load so even with them coupled and in an imbalanced
| heat/cool environment you can still see good performance
| year round.
| bluGill wrote:
| Try to train the hvac profession of that.
| rainbowzootsuit wrote:
| They are required by code to do a load calculation, so
| you might wish to continue shopping around until you find
| one to do it.
| pjc50 wrote:
| British note: UK govt subsidies for some insidious reason
| are not available to "reversible AC" style systems, so the
| dominant form here is air-to-water.
|
| I had mine fitted last year. Retrofitted to existing
| radiators with 8mm pipework. With natgas backup/hot water
| boiler. At the end of this month I intend to go back and
| correlate the bills against the previous year (both kWh and
| PS), because like a lot of discussion in this thread I
| think the installers have made some poor decisions. There's
| too much poorly insulated external pipework.
| santahigh wrote:
| I have this outdoor unit
| https://cooperandhunter.us/product/ch-hyp36lcuo. This past
| winter the temperature dipped into -20C (-11F), had no
| issues maintaining temperature in the low 70s in the house.
| I was running them in heat pump only mode (resistive strips
| were not used).
|
| In the summer our temperature regularly reaches into 90s
| (above 30C) and the house is very comfortable on those days
| as well with the same heat pumps
| bluGill wrote:
| your heat pump is sized correctly for your house.
| cameronh90 wrote:
| I've watched a few videos of his and I'm not sure I'd
| characterise him as entirely skeptical of the technology as a
| whole, but more skeptical of the government incentives to
| retrofit.
|
| He argues in one of his videos that there aren't enough
| qualified installers who actually understand heat pumps, and
| the government incentives are encouraging cowboys, basically,
| to take the government cash and provide unsuitable
| installations. Then secondly, a lot of the insulation
| installers also don't know what they're doing and are
| creating damp problems by neglecting ventilation.
|
| Even as someone who is a huge fan of heat pumps, it's hard to
| disagree with him. There are a lot of difficulties with
| retrofits in the UK, where we have a lot of old terraced
| housing stock with poor insulation, no mechanical
| ventilation, and small gardens. Then on top of that, there
| are almost no tradespeople who actually understand the
| technology or why that housing stock is unsuitable without
| extensive improvements.
|
| To be frank, even regular gas plumbers are shocking here.
| They don't install correctly rated systems, don't set the
| temperature correctly and don't enable the weather
| compensation functionality that is built into all modern
| combi builders and can save you 30%. They just install an
| over-sized boiler and whack the temperature up to maximum. At
| least it keeps the house warm, at the cost of inflated bills.
| That's without getting into the FUD about chemical water
| softening (and use of magic magnetic "water conditioners"
| instead), continued use of loft header tanks and not
| understanding how to improve or balance water pressure.
| jillesvangurp wrote:
| I watched a few of their videos as well. Great stuff. Key take
| away is that there are a lot of installers that have no clue
| what they are doing. Which results in poorly performing
| systems. The issue is not the technology but the lack of
| training and experience.
|
| Another good point is that even an old house with poor
| insulation can benefit from heat pumps. It just depends on
| sizing things properly and dialing things in properly. The UK
| has a lot of old houses that are quite old. This doesn't have
| to be a show stopper. There are a lot of myths and half truths
| around this topic. Of course you'll need more kwh for heating
| if your insulation is bad. But you should still get the same
| energy coefficients. And you'll pay a fortune in gas as well to
| get the place warm. Whether that's worth it with or without
| investing in insulation, windows, new roofs, etc. depends on a
| lot of things.
|
| Most of the nonsense about heat pumps not working at lower
| temperatures is easily refuted by the notion that much of
| Scandinavia runs on these things for decades. Most of the
| people having issues with heatpumps are simply buying the wrong
| stuff, or having it installed wrong, or both. People have
| proper arctic winters in Scandinavia. Also there's a reason
| lots of Scandinavians ended up in places like Montana: it feels
| like home to them but with better summers (it's much further
| south). If people can do heat pumps in northern Norway, Montana
| is a walk in the park.
| trebligdivad wrote:
| How are the COP values so high? The spec on the Vaillant
| aroTHERM+ says ~2.9 but that is showing well over 5 on some;
| what's the difference?
| jnsaff2 wrote:
| COP depends on the temperature difference.
|
| A single COP is some yearly average usually but in these
| measurements it is probably a shorter period.
|
| In europe there is a somewhat more rigorous measure of Seasonal
| COP (SCOP) where the typical climate (in my case nordic) is
| taken as a standardized test. So x number of days outside temp
| 0C, y -5C, z -10C, w +10C etc.
|
| So in case of Air source heat pump if the outside temperature
| is +10 or +15 you can easily get COP numbers that are 9 or
| above.
|
| Better technical documentation usually has rated COP for some
| different outside temperatures or even a graph.
| Kichererbsen wrote:
| note also, that the temperature difference is also influenced
| by the outlet temperature: if you have a radiator system,
| you'll need a higher outlet temperature than say a floor or
| ceiling heating system. this is because the energy
| transported is proportional to area of the delivery system.
| so that's also something to optimize. add in a decent
| insulation (less units of heat required to replace lost heat
| units) and you get a higher COP.
| trebligdivad wrote:
| Thanks! At the top of that webpage is a drop down to select
| the date-range; you can select a year (although there aren't
| that many entries) - and that is lower, I guess averaged over
| it.
| cess11 wrote:
| Where I live every other house is heated by either air-to-air,
| air-to-water or soil-/ground-to-water heat pumps. -20C a large
| part of winter isn't uncommon, some places go even lower.
|
| So to me it looks a little bit insane when people confidently
| claim that heat pumps are unfeasible in rather cold climate.
|
| The best conditions for heat pumps are places with hard rock just
| below the soil, so you can drill a heat well and use it for heat
| storage during summer months, i.e. AC/cooling. In my opinion
| that's the main drawback with air- and soil-based heat pumps,
| can't recycle heat from cooling in the summer.
| __MatrixMan__ wrote:
| Is the kind of well that you'd typically drill for a single
| family dwelling capable of storing enough heat to make that
| worth it?
|
| I know that underground heat storage is popular with district
| heating, where you've got a hollow mountain storing heat for
| the whole city, but the square-cube law means that there's a
| size below which it doesn't make sense. I had only assumed that
| that size was bigger than was feasible for a typical homeowner.
| cess11 wrote:
| Don't need to use cooling to make it work, I live in a fairly
| large house without cooling and a bore down into the mountain
| below is good enough even though we have -15 to -25C for
| weeks during winter. It's in a small town so not an isolated
| location. Most people around here have air-to-water or air-
| to-air, because it's good enough and cheaper to install.
|
| And it's not a hollow, it's a plastic ~1 decimeter pipe with
| ethanol going through stone some distance down from the
| surface. Not sure how long this collector is, but 70-200
| meters is common depending on how large the house is and
| conditions in the ground.
| __MatrixMan__ wrote:
| Interesting, thanks.
|
| Ethanol is an interesting choice... lower specific heat
| when compared with water. Is that to discourage things like
| tree roots from making a home in your well?
| cess11 wrote:
| It's stable, cheap, carries heat OK enough, so it gets
| pumped through the pipe in the ground to collect heat and
| bring it back up to the heat pump.
|
| If there's a leak it's bad since it's quite toxic to
| organic life. If you collect in soil rather than drilling
| into rock tree roots might push around the collector pipe
| a bit over the years but I've never heard about that
| being a problem.
| werdnapk wrote:
| Just got a Daikin heat pump installed this past winter. Electric
| furnace is still used as a secondary heat source. Will have to
| compare more data over the last 12 months, but so far, power
| usage is way down.
|
| I can also integrate home assistant with the Daikin which can
| control all of the functions and it's also able to retrieve a lot
| of useful data that you can use for adjusting furnace and heat
| pump parameters. I can get credit from the power company during
| peak usage times and I'm able to have home assistant interface
| with the heat pump to maximize those credits as well. Very happy
| with the setup so far.
| janten wrote:
| Can you share what you use for the HA integration?
| werdnapk wrote:
| I'm using "Home Assistant Container" on my NAS, but I'll
| likely move to a version installed on a raspberry pi. Daikin
| integration is at https://www.home-
| assistant.io/integrations/daikin/.
| wenebego wrote:
| It would be nice (but potentially difficult) to add the sensible
| and latent capacity for heating and cooling given 3 design days:
| humid, hot, and cold. The btu ratings are useful to compare
| efficiencies but not sizing the system
| matthiaswh wrote:
| If you're interested in installing heat pumps, there is a similar
| open data initiative started by some redditors to aggregate heat
| pump pricing quotes.
|
| https://docs.google.com/spreadsheets/d/1hBebytdBOzLQ4eoAbdFQ...
| stephen_g wrote:
| Really shocked at those prices, I really don't understand
| what's going on in the US/Canada. I could get a 7kW Mitsubishi
| Electric single-head mini-split installed with change for
| AU$3000 here (US$1950) if I buy the unit online and get one of
| the many, many installers around to put it in (fairly simple
| install if it's near an external wall is around AU$750 at the
| moment), but that document has prices in the $7K to $12K for
| that size?!?
| Sytten wrote:
| I paid 15k CAD for 2 Daikin units two years ago, the pricing
| is kinda stupid but it depends on the quality of the model.
| Chinese models are way cheaper than Japanese models.
| bluGill wrote:
| Which is why mini splits are not very popular here. The
| install ends up costing so much. Labor is not cheap in
| US/Canada, and install is a lot of labor. Still seems like it
| should be cheaper though.
| dalyons wrote:
| Labor is even more in australia, so that's not what's going
| on here.
| kleiba wrote:
| Wait until you see prices in Germany...
| dkjaudyeqooe wrote:
| They're only 3.5kW units, but they seem to be the sweet spot
| of mini-split systems locally.
|
| I recently paid 325 euros (about $350) for a unit and 200
| euros (about $215) for installation. They are cheap Chinese
| units but the quality is good in terms of performance. This
| year they might be even cheaper.
|
| Note that 25% of those prices are tax.
| turtlebits wrote:
| Install them yourself! HVAC companies in the US are ripping
| people off.
|
| You can buy a single head mini split for under $800 and the
| tools to install cost under $200, which you can reuse.
|
| If you pick a good location (room with an exterior wall), the
| install is trivial.
| Sytten wrote:
| If you are in North America, I highly recommend to check out
| https://ashp.neep.org/#!/ to compare heat pumps. It has
| efficiency and technical data on almost all models easy to
| compare without the marketing bullsh*t of manufacturers. The
| tests are conducted independently and instead of one COP you get
| the COP depending on the outside temperature which very important
| in cold climates like Canada.
| _spduchamp wrote:
| We moved to heat-pump a few years ago and disconnected from gas.
| It's been working great. Our biggest expense was insulating our
| house. It is an old house and the 2nd floor was very drafty. You
| could feel a breeze coming through cracks in the wall. When we
| opened the wall there were just a few newspapers in there and no
| insulation.
|
| We had the 2nd floor siding removed, an extra layer of insulated
| wall added to the outside and then cladded with siding. It was
| like putting a big insulated hat on our house. Now the
| temperature is very consistent and absolute no drafts.
|
| The architect said to me that we'll never fully recoup our costs
| of putting the hat on the house. To which I replied that we don't
| always to things for economic reasons, and just do them because
| they are the right thing to do.
|
| My only regret was going with a Rheem heat-pump water heater in
| this mix. It does not perform well at all. With hindsight I would
| have looked for a way to perhaps have water heating integrated
| with our air heat-pump system. There is a company called Arctic
| that has those systems.
|
| Also with regard to heat-pump water heater, out big problem is
| that a hydronic floor heating system (installed when we were on
| gas) is now constantly drawing off heat from our tank. I'd like
| to find a small standalone unit to handle floor hydronic heating
| separate from my main water heating.
| belter wrote:
| How noisy is it? I heard of people installing them, and getting
| complaints from the neighbors.
| WirelessGigabit wrote:
| They're as noisy as an AC. So here in Arizona no one cares.
| But in Belgium this was an issue as they run more in winter
| and in winter sound travels further.
| belter wrote:
| Uhmm...I see a problem for countries where you have wall to
| wall connected urban environments...If all 60 connected
| houses on a street, install external heat pumps, it will
| add up.
| toothrot wrote:
| Turns out cities are loud! In NYC, at least, heat pumps
| are far more quiet than the endless window unit A/C's, or
| larger traditional A/C's, in my experience.
|
| Outdoor noise is less of an issue in the winter in big
| cities because windows are closed.
| wussboy wrote:
| Most of the noise in cities is cars. One idiot on a
| Harley drowns out a warehouse of heat pumps
| belter wrote:
| Sounds like an installation can be really tricky or you
| will end up with something like this:
| https://youtu.be/1rKNT7-42J0?t=1510
| cduzz wrote:
| Just installed heat pump systems (daikin) this december.
|
| The exterior unit is basically silent even when there was a
| cold snap (below freezing but not northern alaska cold).
|
| I suspect an interior air source heat pump hot water
| heater, being smaller, will be noisier, and likely less
| efficient.
|
| I'd love to switch my 240v/30a water heater to use a
| 120v/20a service, but will wait a bit longer for the
| technology to mature. Ideally it'd have the heat collection
| part outside.
| triceratops wrote:
| In the winter everyone has their triple-paned windows
| closed. Is noise that much of a problem?
| wussboy wrote:
| Is triple pane common in Belgium? It's not in the UK (as
| far as I recollect) and they're colder than Belgium
| WirelessGigabit wrote:
| I built a house in 2014 there. Triple pane. Pointless.
| You never recoup the cost.
| jillesvangurp wrote:
| Depends on the installer. A lot of noise results from units
| that are not properly mounted or mounted at a slight engine.
| The fan then starts getting more noisy and wears out earlier.
| There are other problems to not installing units properly.
| switch007 wrote:
| Also, when talking about noise it's important to talk about
| frequency. If they produce low frequency noise, that can be
| far more irritating. Shutting the windows won't help much
| kingnothing wrote:
| What problems are you seeing with your water heater? I've had
| one for about a year and have been pretty happy with it after
| learning I needed to schedule high demand times of day. It is a
| bit louder than I'd like but it's not horrible.
| Aurornis wrote:
| > The architect said to me that we'll never fully recoup our
| costs of putting the hat on the house.
|
| Your architect is almost certainly right. I would bet that most
| of your improvements came from fixing the drafts, with the
| insulation providing a marginal improvement on top of that.
|
| I've also dealt with insulating old homes, but I did draft
| fixes, wall insulation, and attic/roof insulation at different
| stages. The draft fixes provided the most improvement, followed
| by attic/roof insulation. Insulating walls had much less effect
| than I anticipated.
|
| In friends' houses I've used my thermal camera (which I didn't
| have back then) and it's easy to see where the heat or cold is
| coming in during weather extremes. These days I'd recommend
| anyone start with the thermal camera view before deciding where
| to spend money on insulation.
| pjc50 wrote:
| Thermal cameras have got really cheap: I found one on
| Aliexpress for less than PS150, that plugs into a smartphone.
| dotancohen wrote:
| Have you tried it, though? Is it any good?
| mpaepper wrote:
| What kind of thermal camera do you recommend and what price
| range?
| andrewblossom wrote:
| I bought a Topdon TC001 a year ago that in my experience is
| significantly more responsive and higher resolution than
| similarly priced FLIR or other name brand options at that
| price point. It appears there are even more low cost
| options now.
| MobiusHorizons wrote:
| I find it rather interesting that companies like FLIR are
| limited by regulation (I believe US export bans) from
| selling IR cameras with greater than 9fps. there is also
| a resolution cap but I forget what it is off-hand.
| Strangely enough this doesn't stop US citizens from
| purchasing higher performing cameras from non-US
| companies. I think technology has come down significantly
| in price over the last few years and you can now get
| smartphone attached versions like infiray for a few
| hundred bucks.
| dotancohen wrote:
| For what use cases is 9 FPS not sufficient?
| tstrimple wrote:
| > Insulating walls had much less effect than I anticipated.
|
| I wonder if that's due to air already being a decent
| insulator and walls have sizeable air voids. As long as you
| cut out the drafts, the air in the walls should remain a
| decent insulator. It's also my understanding that the draft
| treatments are _at least_ as important as the insulation work
| which is done when retro-fitting insulation. One reason attic
| insulation would make a much larger difference is most homes
| with attics use vented soffits designed to encourage airflow.
| They are built to be drafty and you can 't seal up those
| drafts without redesigning things.
| MarkMarine wrote:
| Depends what your walls look like inside. If it's balloon
| framed with no blocking, you'll have a good convection
| current inside the wall.
|
| The moisture concerns when trying to add insulation to an
| old uninsulated house are real, in service of saving a few
| thousand dollars of heating costs you could literally
| destroy your house and your health with mold.
| zer00eyz wrote:
| Someone is going to come by and look at your comment and
| raise an eyebrow.
|
| The building trade and construction is filled with nerds,
| amazing products, cheats and snake oil... so just like
| tech but less VC'c.
|
| https://en.wikipedia.org/wiki/Building_science building
| nerds are on point and doing all kinds of cool stuff. If
| you want the modern version of bob villa this old house
| is probably this: https://www.youtube.com/@buildshow . It
| will give you some clues as to what is going on in modern
| construction.
| MarkMarine wrote:
| Oh I've seen buildshow. I have also seen him talking
| about mistakes he made in the older designs he had. I
| would be real cautious about letting a builder at a lower
| tier than him beta test their ideas on moisture control
| inside my walls when I'm the test dummy inside.
| dylan604 wrote:
| Even if you don't use a thermal camera, just the thermal
| thermometers work as well. Sure, you have to take more
| readings, but the result is the same. A lot of people
| probably have one of these now after Covid, and can at least
| test things out before going to the step of a full thermal
| camera.
|
| I have a bedroom that has a shared wall with a water heater
| which causes this room to be hotter than the rest of the
| house. Using the thermometer showed the temps after I added a
| barrier to the inside of the utility closest dropped
| significantly.
| jbjbjbjb wrote:
| On the payback period, that's probably just outlay divided by
| energy savings. I'm sure you'd get more enjoyment from a more
| comfortable house and the next owner will appreciate the
| modernisation too so those need to be factored into the
| investment appraisal.
|
| I doubt the architect puts such a miserly lens on the other
| projects they're involved in.
| jillesvangurp wrote:
| This is actually becoming an important point. In parts of the
| world where energy ratings matter, they have an impact on
| house value as well. They unlock incentives, etc. A house
| that is up to modern standards is simply worth more because
| any new owner does not have to do expensive renovations to
| modernize. In the Netherlands house flipping is pretty
| common. Buy something old, modernize it, live in it a few
| years and make a profit. The lower energy cost is both a nice
| bonus and a key selling point.
| mecameron wrote:
| > The architect said to me that we'll never fully recoup our
| costs of putting the hat on the house. To which I replied that
| we don't always to things for economic reasons, and just do
| them because they are the right thing to do.
|
| I am so frustrated with this analysis and sentiment when it
| comes to environmental investment. I understand that looking at
| it with a financial lens can and should be done to inform what
| we do, and it would be great if a project just paid for itself,
| but you look at all the other things we spend money on and the
| same calculus is not used.
|
| People don't buy the cheapest car, house, clothing, or food
| they could possibly get by with, or analyze the marginal cost
| of moving up or down the possible price tiers available to them
| with only the financial payback as a guide. Yet we constantly
| hear the refrain that you shouldn't spend a given amount of
| money on solar, house improvements, appliances, etc. that might
| be better for the environment if the payback isn't somehow
| positive with a 10-20 year payback period.
|
| I've constantly had to work with contractors to let them know
| that I still want to pay for the marginal costs associated with
| investment even knowing that the marginal financial benefit is
| smaller. For instance, with solar panels in less than ideal
| locations, tri-pane windows, etc. I have disposable income, and
| I think the world is trouble for the 8+ billion humans
| inhabiting it, so I think it's worthwhile that I would spend
| some of that to make it marginally better even if that means I
| don't have a positive financial return.
| jancsika wrote:
| > so I think it's worthwhile that I would spend some of that
| to make it marginally better even if that means I don't have
| a positive financial return.
|
| Your action is going to make close to 0% difference for the
| 8+ billion humans inhabiting the planet. So from a practical
| standpoint, you've failed, but that practical failure makes
| it clear that the gesture has pure symbolic value for you.
|
| And since that symbolic value stands in stark contrast to
| incessantly chasing positive financial returns: task failed
| successfully. Congratulations!
| toomuchtodo wrote:
| From a practical standpoint, they have valued their energy
| savings closer to what the true cost of carbon emissions
| are (remember, most carbon emitters are in no way paying
| the true cost of their emissions [1]; this externality
| dumping continues with wild abandon).
|
| You're arguing systems and scale. This person is simply
| early in the adoption curve. Consider what will happen when
| this happens more broadly. As the climate situation becomes
| more dire [2], the price of carbon emissions per ton will
| rise and the willingness to prioritize energy savings and
| carbon emission reductions should increase regardless of
| fiat return. Physical system outcomes are distinct from
| magic number in database goes up.
|
| But sure, if you're already poor and have nothing [3], this
| won't matter to you and your life trajectory is already
| mostly locked in today. As nullstyle mentions, we need to
| compound in the positive outcome direction, and those
| decisions are being made today.
|
| [1] https://www.nature.com/articles/s41586-022-05224-9
|
| [2] https://www.npr.org/2024/04/09/1243595924/march-world-
| hottes...
|
| [3] https://ourworldindata.org/poverty
| taeric wrote:
| This is a tough one, honestly. For one, being at the
| early adoption curve also has you on the low side of
| efficiency. If things aren't being done at scale, they
| are likely fairly low on that score.
|
| More, though, moving to something that gets you a more
| climate controlled home in the name of efficiency is odd.
| You could almost certainly use smaller scale solutions to
| get more comfortable living that does not involve such a
| drastic change to the home. Clothing and lifestyle
| changes are things you can do, for one. For two, though,
| if the place was so drafty you could feel a breeze, it
| almost certainly did not have active heating/cooling to
| the level that they built up to. Such that is seems odd
| to justify how efficient you could do something that was
| just not getting done before?
|
| No reason not to do it, of course. But insulation is an
| expensive thing to add to a house. Not just in raw costs,
| mind. Most insulation materials are of dubious carbon
| neutrality. And nothing lasts forever, least of all
| housing.
| toomuchtodo wrote:
| Insulation is one of the cheapest improvements than can
| be done to improve energy efficiency of a structure. Once
| insulated, those energy efficiency gains persist for the
| life of the structure. Nothing lasts forever, but homes
| have a 100+ year service life.
|
| https://www.whitehouse.gov/briefing-room/statements-
| releases... (control-F insulation)
|
| https://www.energy.gov/energysaver/types-insulation
|
| https://www.energystar.gov/saveathome/seal_insulate/metho
| dol...
| taeric wrote:
| Homes have a 100+ year service life? Where? I see the
| median age of housing stock varies heavily in the US.
| Quickly scanning other markets, I see EU has older
| housing, in general. Even there, though, they don't talk
| of 100+ year old houses as being that common.
|
| Scanning websites on this claim, I see that "properly
| installed, with no damage" some types claim up to 100
| years of service for insulation. I strongly suspect that
| that is a claim that will not hold for the vast majority
| of homes. More reading also strongly suggests that if
| your house was built prior to 2005, you probably need to
| get the insulation redone.
|
| Worse, from my experience, the older the home the less
| likely you are to have subfloor/walls to actually install
| insulation. Heaven help you if you do one of those
| container homes. And if you live in an environment where
| you have heavy rains or hail, expect damage to creep in
| rather quickly.
|
| Don't get me wrong, I support the idea that adding
| insulation is almost certainly a good idea where you can.
| I just can't bring myself to trust claims of 100 year
| service life.
| wahnfrieden wrote:
| There's no consumer-led revolution to come from early
| adopters accruing over time. It's fringe and luxury
| activity.
| masterj wrote:
| You... clearly haven't tracked the cost of solar panels.
| Learning curves are a thing
| https://ourworldindata.org/learning-curve
| barbazoo wrote:
| > As the climate situation becomes more dire [2], the
| price of carbon emissions per ton will rise
|
| Looking at what's happening here in Canada, where it
| looks like what has high chances to be the next
| government is campaigning on getting rid of the carbon
| tax, these days I'm somewhat pessimistic that carbon
| pricing will actually be implemented by the top
| contributors to global emissions. I hope I'm wrong.
| nullstyle wrote:
| "Close to 0% difference", compounding over time was how we
| got here. I'm not saying personal responsibility is the
| only factor, but youre the wrong person in the exchange
| above, and OP has the proper attitude.
|
| Better is always good
| zackmorris wrote:
| I don't know, I've always dreamed of a world where
| influential people like yourself saw the value in leading
| by example.
| burkaman wrote:
| Literally every single accomplishment in human history was
| built upon millions of small "symbolic" individual actions.
| Good things don't just magically happen on their own.
| ApolloFortyNine wrote:
| It's a much more complicated equation, but it's very possible
| the emissions from simply producing the insulation and having
| the install done are more than the saved future emissions.
| wizzwizz4 wrote:
| It is possible. You can't measure that in currency, though.
| malfist wrote:
| If there was a carbon tax you might be able too.
| gregwebs wrote:
| Insulation pays back over a long enough time horizon
| (economically or CO2 wise). Although spray foam at the
| moment does have a large CO2 impact. If someone is putting
| in way too much insulation then we could say that the last
| 30% of insulation wasn't worth it. When people say
| something won't payback economically on a home, they are
| usually looking at a time frame of 10 years or less.
|
| In this case the insulation itself will probably payback
| quickly. The problem is the cost of re-siding the house to
| get the insulation in- likely similar for CO2 impact.
| adrianN wrote:
| That's very unlikely. Insulation lasts decades and is not
| that difficult to produce.
| slashdev wrote:
| Is not impossible. It's not likely either.
| mrspuratic wrote:
| I absolutely agree this kind of nontrivial work can be done
| in a way that is woefully inefficient/impractical. My EWI,
| approx 85m2 of graphite polystyrene with an embedded CO2[1]
| of ~15kg/m2 is equivalent to approximately 1.5 years of CO2
| emissions (combined electricity & gas), or ~9 months of CO2
| emissions before I replaced windows and old kerosene boiler
| that came with the house.
|
| Actual installation and other materials excluded
| (adhesives, mesh, silicone render, 450 hot beverages,
| getting the neighbour's car repaired after the scaffolders
| hit it, etc.) excluded.
|
| I don't have a full year of data yet, but all in it's
| looking like CO2 emissions are going to come in at well
| under 40%. This is in line with the independent assessment
| I needed to clear a grant for some of the costs[2]. It
| seems to me "carbon ROI" is about 1/4 the financial ROI
| (est 8+ years).
|
| Now if it was PU instead of EPS that would be a different
| cost (10x the CO2 of polystyrene). Sadly I also ended up
| with some PU (PIR) in a small area of low-pitched roof
| void, I don't know if there were better choices there.
|
| There's also a hidden cost in living in a cold, damp
| building - now there are winter days when I don't even turn
| the heat on at all.
|
| [1] https://www.greenspec.co.uk/building-design/embodied-
| carbon-... [2] https://www.seai.ie/publications/Your-Guide-
| to-Building-Ener...
| flightster wrote:
| > People don't buy the cheapest car, house, clothing, or food
| they could possibly get by with... Yet we constantly hear the
| refrain that you shouldn't spend a given amount of money on
| solar, house improvements, appliances, etc. that might be
| better for the environment if the payback isn't somehow
| positive with a 10-20 year payback period.
|
| I think the key thing here is that energy is 100% fungible
| unlike your examples. A kWH is a kWH.
| Scoundreller wrote:
| Sorta, around here, a bucket of kWh at 2PM sells for more
| than the same sized bucket at 2AM.
| dap wrote:
| But you're not buying kWh in this example. You're buying
| home energy systems. They have many tradeoffs, pro and con.
| Besides that, for many people, a kWh produced by a
| renewable energy source or that's available to them when
| the grid is down is worth more than one produced by a coal
| plant that might be unavailable during an outage.
| hgomersall wrote:
| No, it really isn't. Your house might lose the same total
| energy as a super efficient house, but if all that energy
| happens to be lost through a cold spot by your dining room
| table, you're going to get pretty fed up with the
| situation.
| adrianN wrote:
| Imo you recoup the cost via the value of the building. Who
| wants to buy a drafty house with an oil furnace after 2030 or
| so?
| mortify wrote:
| No one will pay more for a house with a higher R-value. If
| this were a determining factor, it would be part of real
| estate listings. It's a secondary or even tertiary concern
| for most people.
| adrianN wrote:
| Where I live you even get better conditions on your loan
| if you buy a house with better insulation, it's that
| important.
| toomuchtodo wrote:
| If you're buying a house without asking for the trailing
| twelve month energy bills, you are an unsophisticated
| real estate market participant and will pay for the
| ignorance over time.
| ossyrial wrote:
| > If this were a determining factor, it would be part of
| real estate listings.
|
| It is part of real estate listings in the Netherlands,
| and it very much affects the value of the building.
| https://www.tilburguniversity.edu/nl/actueel/nieuws/meer-
| nie...
| LunaSea wrote:
| PEB grade systematically increases the value of a house
| less than 20% of the house value.
|
| That's far too low to justify the huge sums involved in
| energy renovations.
| dfxm12 wrote:
| It shouldn't be a surprise. Our economic system and even
| economics-related media puts individual short term gains
| above all else. Everything is viewed through the lens of
| "what makes _me_ the most money today? " Long term positions
| are not valued. Positions that might benefit others are not
| even considered.
| rahimnathwani wrote:
| Long term positions are not valued.
|
| Stock market? Positions that might benefit
| others are not even considered.
|
| ESG?
| zardo wrote:
| > The architect said to me that we'll never fully recoup our
| costs of putting the hat on the house. To which I replied
| that we don't always to things for economic reasons, and just
| do them because they are the right thing to do.
|
| I agree, what kind of hat is your house wearing?
| _spduchamp wrote:
| The outter layer wall that was added was wood studs, rock
| wool insulation, then wood siding. Looks great, no drafts,
| even temperature year round without having to run the heat-
| pump much. We also have an ERV to keep the air fresh in the
| house.
| hgomersall wrote:
| It's not just an environmental consideration - efficient
| houses are much more pleasant to live in, particularly if
| they are designed holistically with proper ventilation
| systems and few cold spots.
| mataug wrote:
| > My only regret was going with a Rheem heat-pump water heater
| in this mix. It does not perform well at all.
|
| Heat-pump water heater's performance depends a lot on where its
| installed and the airflow+heat available. If the water heater
| is undersized or if there isn't enough heat in the air, it
| would perform worse than a standard gas/electric water heater.
|
| Mine is installed in a closet under the stairs, which is not
| ideal, but as long as I keep the water heater in eco mode, and
| keep closet door slightly open, it works good enough for our
| usecase. Our annual water heating costs went down from ~$500 to
| ~$100 after switching to the heat pump water heater.
| usrusr wrote:
| As in the cold end of the heat pump is inside the heated area
| of the house? That feels very weird. On the other hand with
| heat pumps, stacking multiple stages strategy isn't
| necessarily a bad thing! All inefficiencies are not really
| losses but merely resistive heating contributions (unless
| their heat escapes to the final cold sink aka outside) and in
| the end the real question is which configuration is good in
| terms of capex and maintenance.
|
| In an environment where getting rid of humidity is a concern
| (mold!), a "cold end inside" heat pump for water might even
| double as a dehumidifier, with water condensing on the cold
| end sent to the sewers, contributing a little energy in the
| process.
| sf_rob wrote:
| That's not uncommon and is even beneficial in warmer
| climates. It will be parasitic in winter (even if
| externally vented) and symbiotic in summer.
| loceng wrote:
| Have you ever monitored the air quality levels in various
| rooms?
|
| Curious if getting rid of those drafts may be unknowingly
| affecting your health in other areas.
| doctorhandshake wrote:
| My understanding is that any house that isn't built 'tight'
| _by today's standards_ will have a fast enough ACH that you
| don't need to worry about ventilation as you would with a
| tight house. And only a 'deep energy retrofit' of an older
| house would result in tightness like that, so ERV and MUA etc
| are not necessary. Local code, build detail, and age of house
| are factors, YMMV, but this isn't a problem you'd cause by
| accident with anything but a very invasive retrofit.
| amluto wrote:
| Mechanical ventilation is not _necessary_ in a drafty
| house, but it's still _very_ nice to have. Bonus points for
| a well-filtered system. (None of the major brands will sell
| you a system that is well filtered out of the box. But it's
| straightforward, if rather space consuming, to put a
| monstrous filter with effectively zero pressure loss in
| series with the system.)
|
| Bonus points for taking advantage of a balanced ventilation
| system's ability to continuously extract air from stinky
| areas, e.g. bathrooms.
|
| Even more bonus points for avoiding negative pressure due
| to conventional bathroom exhaust, which can defeat stack
| effect-based exhaust from non-power-vented combustion
| appliances, which are, for some reason, still legal.
|
| (Seriously, WTF. There's a straightforward design that
| could safely created a forced draft even with legacy leaky
| ductwork: put the fan on the _exterior_ vent terminal, so
| the duct is under negative pressure. The wiring could be
| fished _through the existing duct_ using class 2 / SELV
| wiring with high-temperature insulation. A pressure or
| airflow-sensing interlock in the appliance could prevent
| gas flow if the fan stops working. Sadly, I've never heard
| of a system remotely resembling this. The choices appear to
| be stack effect (category I or II) but basically crossing
| fingers and hoping the pressure works out) or positive-
| pressure sealed but not tested "category III" or "category
| IV" pipes and crossing fingers and hoping that the pipes
| are actually airtight.)
| doctorhandshake wrote:
| Yeah I believe GOLogic's designs have the ERV exhaust in
| the kitchen, bathroom, and laundry, and the fresh air
| return in the living spaces and bedrooms. I definitely
| like the idea of that, especially with filtration.
| ip26 wrote:
| Drain water heat recovery seems like the best efficiency boost
| for water heating. Completely passive, 60% extra heat energy.
| At least for cold climates. Heat pump water heater might be
| phenomenal in a Phoenix garage.
| _JamesA_ wrote:
| A heat pump water heater seems phenomenal to me in an Austin
| attic. And I use the cold air generated to cool a
| wiring/server closet. Win/win.
| rayiner wrote:
| There's a couple of big problems with the heat-pump industry in
| the U.S. First, people get their advice about HVAC from the
| tradespeople, who are way behind the curve on heat-pump
| technology. Second, and relatedly, the trusted American HVAC
| brands are far behind China and Japan and Europe on heat pump
| technology, especially cold-weather capable inverter units.
|
| I had our heat pumps replaced here in Maryland in 2019-2020
| with mid-range Amana (rebranded Daikin) units. Decent
| efficiency, but output drops to half at 10F. The guys who
| recommended the system, a trusted local business, didn't even
| tell me about that. Even in Maryland that means waking up to a
| cold house several weeks out of the year. That means we needed
| to keep our oil-based backup heat in place, which is a huge
| expense to maintain. (Also, our HVAC guys didn't know that the
| communicating Daikin units can't control external auxiliary
| heat, so they just left things with no backup heat whatsoever.)
|
| After educating myself about this, I wish we had installed one
| of those Chinese inverter based units, like the Gree Flexx. But
| if I asked my HVAC guy about that they'd stare back blankly.
| And the folks who do know what they're doing can charge
| whatever they want. The price of getting a mini-split installed
| here is several times the price of the unit. The $16,000 we
| spent just a few years ago for two condensers and air handlers
| looks downright cheap compared to what it would cost today.
|
| Regarding your floor, we have a similar situation with radiant
| heat in our basement slab. I've been looking to ditch our oil
| boiler, but there's basically no heat pump options that are
| widely available. (I don't want to install some imported
| Chinese air to water heat pump that the local guys can't fix.)
| With heating oil prices being over $4, though, I'm looking at
| just biting the bullet and installing an electric boiler, which
| is at least something I could probably fix myself.
| mrb wrote:
| I feel you. The lack of knowledge among American tradespeople
| is infuriating. As soon as you deviate slightly from the
| brands of furnaces they have been installing for decades,
| they don't know anything.
| danans wrote:
| > The architect said to me that we'll never fully recoup our
| costs of putting the hat on the house.
|
| That's only true if value your added comfort at a very low
| price. The problem is that it is hard to put a value on the
| comfort of a house, either while living in it, or while selling
| it. Hotels, however, do it all the time, but it's easier since
| they are in the business of selling comfort at various levels.
| 1123581321 wrote:
| That's a shame about the Rheem. Ours has been overperforming my
| financial model in the standard eco mode. We do have an
| advantage in that it sits out in the open in the unfinished
| part of the basement, which runs slightly warm in the winter
| due to a ductwork problem. No venting was necessary.
|
| It's definitely challenging to find trades who have both the
| knowledge and interest to innovate relative to standard HVAC
| installations in the area.
| GenerWork wrote:
| >My only regret was going with a Rheem heat-pump water heater
| in this mix. It does not perform well at all.
|
| Sorry to hear that. My Rheem heat-pump water heater works
| fantastically, although I do live in a hot climate so that
| could be why.
| mechagodzilla wrote:
| Wait - you have a HPWH connected to a hydronic floor system?
| That's an extremely inappropriate setup - the heatpump on a
| rheem is probably like ~4000 BTU/hr, and it's pulling the heat
| from the conditioned space, then you're drawing it off and
| pumping it back into the space via the floor. If you don't have
| an air-to-water heatpump and don't want fossil fuels, just use
| an electric boiler.
| Merad wrote:
| I think the biggest hurdle to heat pump adoption (at least in
| North America) is likely to be that it provides an experience
| that simply isn't as good as a gas furnace. On a chilly morning
| the air coming out of the vents just isn't that warm and it may
| take hours to bring the house up to temp, whereas gas puts out
| pleasantly warm air immediately and can quickly warm the house
| even on the coldest days. When it's truly cold (like < 20F) the
| heat pump will run continuously and struggle to maintain temp.
| Don't misunderstand, the heat pump is certainly _good enough_,
| but people typically don't pick the "good enough" experience
| over the "better" experience when the better option is
| available and they can afford it.
|
| For reference I've lived in NC and TN near the mountains where
| heat pumps are pretty standard. I imagine we don't get the
| ultra high efficiency cold weather heat pump units that would
| be used up north, but they also get much colder temps than us.
| Several of the houses I've lived in have been recent
| construction (2008 and 2018), so well insulated and reasonably
| new & efficient heat pumps. For the last 2 years I've been in a
| house with gas, and it's just so damned pleasant... I know on
| paper that heat pump is better, but I really don't want to give
| up that furnace.
| antisthenes wrote:
| > I think the biggest hurdle to heat pump adoption (at least
| in North America)
|
| > When it's truly cold (like < 20F) the heat pump will run
| continuously and struggle to maintain temp.
|
| Luckily, pretty much the entire Western and Eastern Coastal
| areas, it doesn't actually get that cold on a regular basis,
| except a few days in the winter. The US is actually in an
| incredibly advantageous geographical position for at least
| 60% of households to be on heatpumps, as opposed to, say,
| Finland/Canada/Russia etc.
| napoleongl wrote:
| Meanwhile it was estimated that half of Swedish houses were
| equipped with heat pumps in 2016. That number has certainly
| not gone down since given the steep rise in electricity
| costs we've had since. Many houses have been converted from
| horribly inefficient direct electric heating to heat pumps.
| Mvandenbergh wrote:
| Part of the problem is that heat pumps aren't really well
| suited to a use case where you frequently have to bring a
| house up to temp in the way you're describing. If you have a
| big overnight set-back and then the heating comes on in the
| morning, that will require much more heat output than
| constantly putting out enough heat to maintain temperature.
|
| In a well insulated property, the greater efficiency from
| operating at low output temperatures outweighs the additional
| heat loss from no / a low overnight set-back. In a poorly
| insulated property, the optimum set-back is higher and the
| efficiency at that optimum point is also much lower because
| the heat pump has to operate at higher temperature in order
| to ramp up the temperature.
|
| I don't know if they are available in North America, but in
| the UK we have hybrid systems available that use heat pumps
| for 80% of the annual heat load and gas for peaking /
| ramping. OpenTherm gas boilers can be retrofitted to be
| controlled in this way so you only add the heat pump. An air
| source heat pump driving a hydronic / radiator system in this
| climate can serve 80% of the annual load with a unit sized at
| 55% of peak heat load. Different climates will have slightly
| different numbers but it shows the power of a hybrid system
| as you save a lot on HP capex and also maintain redundancy.
|
| The advantage of this system is that the failure-mode of an
| incorrectly sized system is an efficiency penalty rather than
| not being warm enough, the same as an incorrectly
| commissioned or sized gas system. (Most gas systems are not
| optimally sized or configured and are delivering 5% to 10%
| less efficiency than they could).
|
| I don't know if these systems are available in ducted air
| configuration for the US market though.
| Ataraxic wrote:
| It doesn't have to be all heat pump. You can have a backup
| gas heat for the coldest days, or even resistive heat. I'd
| bet there are heat pumps that integrate those technologies to
| ensure a nice experience.
| mholm wrote:
| When I got a quote to upgrade my resistive heater to a heat
| pump, the added cost to get a backup resistive heater (with
| the same capacity as my existing one) was only $500. Seems
| like as long as you're wired for it, it's very cheap.
| SECProto wrote:
| A relative recently upgraded their 120yr old house with heat
| pumps, and the warmth is so much better than where I
| currently live (a 40 year old home with a new gas furnace).
| In my experience you can't generalize about heat source.
| zmully wrote:
| What would make this even more useful (if possible) would be
| including 1) the UK equivalent of an ASHRE Manual J and 2) an ACH
| rating for the dwelling.
|
| Heat pumps are great, but suffer from piss-poor installations and
| shitty salespeople. When I renovated my DC rowhouse, I talked to
| 6 different companies about the HVAC install. Only one, ONE,
| would do a Manual J. I had already done a Manual J myself (it's
| not hard at all) so I could compare their calculations to my own.
| They were slightly different (they calculated a greater load than
| I, but at the time, the insulation systems I used in the house
| were uncommon, so most of this difference was due to their lack
| of familiarity).
|
| In the end, my rowhouse needed such a small unit (1.5T IIRC) that
| I couldn't get the SEER I wanted because no one makes high end
| units that small... I ended up slightly oversized at 2T, but that
| was necessary to get a unit from a good manufacturer (Lennox),
| rather than a pile of garbage flipper grade unit from someone
| like Goodrich.
|
| What the heat pump industry is going to suffer from is the utter
| and blatant disregard to right-sizing units. The other 5
| companies I talked to? They just walked around the house and then
| said shit like "This gonna need a 5T unit" and left.
|
| Also, flex duct is bane of any central non-high velocity system.
| If an installer mentions flex duct for anything other than a
| short run to a register, run away from them. Flex duct is the
| sign of a lazy installer who is going to cut corners everywhere
| else they can, and especially where you can't see it.
|
| In the same vein, if the installer doesn't have their own sheet
| metal shop, make damn sure they're buying your ductwork from a
| sheet metal shop and not from HomeDepot. One company I
| interviewed refused to do a Manual D (duct sizing) and said that
| a standard (i.e. we're going to get it at HomeDepot) 9x13 duct
| will be "plenty" for the return. The return (per the Manual D)
| ended up barely fitting in the chase alloted for it which is
| something like 30"x 24".
|
| So be educated consumers:
|
| - Do a Manual J and Manual D yourself, they're not hard
|
| - Right size your unit. It should be running 90% of the time for
| max efficiency, so yeah, a smaller unit might take longer to cool
| or heat, but you shouldn't be turning the unit on or off but two
| or three times a year. A super high efficiency unit that is
| oversized is going to be terrible and inefficient. Don't fall for
| their shitty sales tactic of "but it's not going to be able to
| cool your house down as quickly as this 5T unit!".
|
| - Demand good work. Like a plumber, never ever ever let an HVAC
| installer in your house unmonitored. I had to fight with my
| installers because they wanted to move a chase to the middle of
| the room "because it'll be easier for us". No, you have the
| plans, you quoted on the plans, so I don't give a shit that it's
| hard.
|
| - Insulate and seal your duct work. You can't go back and do
| this, so make sure it's in your contract, and make sure they
| actually do it.
|
| - Make sure you service your unit annually, it's a couple hundred
| bucks of peace of mind.
| dopylitty wrote:
| This guy[0] has done quite a few deep dives on heat pumps that
| cover a lot of the myths (eg they don't work in the cold). It's
| pretty interesting material if you're thinking about a heat pump.
|
| It has always seemed silly to me that we spend money to keep a
| box of cold (fridge) inside the houses we're spending money to
| heat in the winter and spend a lot of money to heat up dryers,
| stoves, etc in the houses we're spending money to cool in the
| summer.
|
| Watching these videos made me think there's a real possibility at
| some point to have something like a whole home heat pump that
| just moves heat from where it is to where you want it and in the
| process reduces the need for systems working against each other
| to heat/cool specific parts of the house. I understand there's
| something in commercial settings that has this capability but I'm
| blanking on the name.
|
| 0: https://www.youtube.com/watch?v=7J52mDjZzto&t=0s 1:
| https://en.wikipedia.org/wiki/Variable_refrigerant_flow
| FredFS456 wrote:
| My parents have always had an "outdoor fridge" that is a
| stainless steel equipment box that my dad salvaged from the
| junk pile at work. They put food in there that is less prone to
| spoiling, and use it through the fall/winter/spring months.
| dopylitty wrote:
| That's a great way to keep the raccoons out!
|
| If I make a big pot of soup in the winter I will cool it down
| outside before putting it in the fridge. That way it gets
| down below the zone where bacteria grow much faster than if
| it were inside.
|
| From an energy perspective it would be better to put it in
| the fridge so the heat would be removed by the fridge and
| stay in the house rather than dissipated outside but as far
| as I know the heat would also end up in the other goods in
| the fridge causing potential spoilage. It would be nice to
| have some kind of remote chiller pot hooked to a heat pump
| that would just pump the heat out of the soup and into a cold
| room.
| brnt wrote:
| > heat pump that would just pump the heat out of the soup
| and into a cold room.
|
| You already have one, it's your fridge ;)
| dopylitty wrote:
| Right! The problem is before the heat gets to the room it
| sits in the milk for a while and raises it to
| temperatures where bacteria like to be.
| changadera wrote:
| My neighbour has a heat pump and it's kind of annoying when
| running because the 180hz hum is audible in most of the rooms in
| my house. This in the UK and our houses are detached, but fairly
| closely spaced.
| dv_dt wrote:
| I wonder if there is some isolation dampers that could be added
| to the mounts (sounds fancy, but think rubber or silicon
| grommets).
| timbit42 wrote:
| Most heat pumps mounts I've seen have rubber grommets but
| older heat pumps will make audible noise as they wear out.
| switch007 wrote:
| A constant hum from a neighbour's heating unit would drive me
| crazy. We have lots of terraced and very-close-together housing
| in the UK...
|
| Low frequency noise can travel quite far (and through mass), so
| not even distance helps that much
| nirolo wrote:
| A very big database comparing a lot of relevant data can be found
| at https://www.eurovent-certification.com/
|
| I only used it for air-to-air heatpumps (or air conditioners as
| they are sometimes called). He the data is oretty good. I can't
| say anything about the other types of heatpumps but I've found
| the database quite useful.
| apexalpha wrote:
| How do these people monitor the heat output of the heatpump? Is
| that something you can get from the device itself?
|
| I recently installed a Nibe S2125 in my house, it's been running
| great except I don't monitor electricity consumption of just the
| heat pump, nor do I know how to get the heating output.
|
| I somehow doubt all these people have a specific electric meter
| on their heatpump, or do they? Mine runs on 400V and the meters
| are a bit expensive to get just for the data.
| willcipriano wrote:
| Anyone make/is it feasible to make: a window unit heat pump?
| apexalpha wrote:
| Midea Window AC is what your looking for I think.
| willcipriano wrote:
| Yeah close, they don't seem to support "heat and cool" with
| those heat pump style units yet but that's a minor
| requirement.
|
| I'll probably try one this year. Looks cool if nothing else.
|
| https://www.midea.com/us/air-conditioners/window-air-
| conditi...
| matznerd wrote:
| I love to see Hacker News geeking out on heat pumps and that this
| is currently on top of the home page!
|
| Don't forget that this community has an outsized influence on the
| world as early adopters and innovators.
| kleiba wrote:
| Heat pump technology is certainly out of the "early adopters"
| phase. It is basically the standard for new buildings in Europe
| (at least Northern Europe, I'm not sure about the South), and
| has been for years.
|
| In Germany, where I currently live, they recently passed a law
| that constrains what kind of heating system you're allowed to
| put into your house to a point where basically only a heat pump
| fulfills all criteria (perhaps with the exception of pellet
| heaters).
| danans wrote:
| It wasn't clear to me what kind of monitoring equipment is being
| used to gather this data, or whether it's just being manually
| gathered and reported by each system owner.
|
| If the former, I'd like to get the generic equipment to use to
| monitor my heat pump system, and if the latter I wonder if the
| resulting inaccuracy results in improbable outliers like the
| system with 6.0 COP.
|
| EDIT: it's a bit buried, but the systems are monitored using Open
| Energy Monitor (https://docs.openenergymonitor.org/applications/h
| eatpump.htm...), and it seems like heatpumpmonitor.org was
| created by them.
| supermatt wrote:
| I love my ground-source heatpump. I did the entire install
| myself, submerging the loop in the pond by my house. We get a COP
| of approx 3.0 in the middle of winter when its -25C air temp
| outside :)
| WaitWaitWha wrote:
| do you have your setup documented online somewhere public?
| joshlk wrote:
| Is there an explanation of the acronyms/metrics used? E.g. COP
| karussell wrote:
| COP is https://en.wikipedia.org/wiki/Coefficient_of_performance
| (the higher the better). And SCOP is seasonal COP.
| timbit42 wrote:
| COP or CoP means co-efficient of performance. An electric
| heater has a CoP of 1. New heat pumps usually have a CoP of 4
| or higher. My 11 year old heat pumps have a CoP of 3. This
| means they can produce 3 or 4 times as much heat as an electric
| heater, assuming the same amount of electricity, or produce the
| same amount of heat with 1/3 or 1/4 of the electricity.
|
| At a CoP of 3, they are more efficient than electric heaters
| down to -15C. At a CoP of 4, down to -25C. There are better
| heat pumps coming with a CoP of 5.
| adev_ wrote:
| My still-running heat pump from 1981 is not in the list.
| Unacceptable ! :)
| karussell wrote:
| There is another very helpful list of heat pumps (German):
| https://cloud.skip.scientists4future.org/s/xwxiykjZnXaAtng
|
| This is based on the "Bafa" list but filterable und sortable
| (https://www.bafa.de/SharedDocs/Downloads/DE/Energie/beg_waer...)
| class3shock wrote:
| I just want to throw this out there to this audience. As someone
| that has worked in and been interested in energy efficient
| housing for 10+ years, I have been heartened to see the start of
| proliferation of heat pump units. However, as a whole, the market
| seems to be flooded with units of as good quality as your normal
| store bought air conditioner. That is to say, as soon as
| something goes wrong with them, they are garbage.
|
| How come we only talk about efficiency/environmental friendliness
| of use and not of the unit itself (and all it's embodied
| energy/cost)? If I save 60% on energy for heating every year but
| then require all the energy needed to build a new heat pump every
| 5-10 what am I really doing?
|
| I would love to see an effort to create an open source heat pump
| itself, based off of COTS parts and raspberry pi or something
| similar where you are not locked out of the software and
| dependent on a supplier to have replacement parts that they
| probably stopped stocking 5 years after releasing the product.
| Kerb_ wrote:
| >If I save 60% on energy for heating every year but then
| require all the energy needed to build a new heat pump every
| 5-10 what am I really doing?
|
| >As good quality as your normal store bought air conditioner.
| That is to say, as soon as something goes wrong with them, they
| are garbage.
|
| Sounds like you're still saving 60% on energy because the
| status quo is also disposable appliances. It absolutely sounds
| better than nothing to me, but I am also hopeful for more
| maintainable and accessible heat pumps in the future. I haven't
| heard about any efforts for an open source heat pump, but I'm
| definitely interested in something like that myself
| londons_explore wrote:
| Quality cones with design refinements learnt after the
| technology has been in people's homes for decades.
|
| There is nothing theoretically unreliable about a heat pump -
| it would totally be possible to design it to work for 50+ years
| with just basic filter replacements.
| Pxtl wrote:
| > store bought air conditioner
|
| Yup. Saving the world is going to be ruined by Chinese
| shovelware-quality equipment re-stickered with American brands,
| but in this case it's even worse since you're hiring a
| professional installer and those guys will only work with a
| short list of manufacturers, so getting somebody to install an
| expensive quality European model will be basically impossible
| (if they're even certified for use in North America).
| turtlebits wrote:
| Asia has been using mini splits for at least 50 years,
| Chinese made units are reliable, and the expensive brands are
| generally made there too.
| the__alchemist wrote:
| Hey - I've been following the steady stream of articles and
| discussion here about heat pumps, so I have a question that is
| tough to answer from the articles.
|
| Is heatpump popularity regional? My understanding was that heat
| pumps are the technology behind residential AC, heating, and
| commercial HVAC. Thermodynamic 4 step cycle of a working fluid
| with expansion, compression etc. Every house I've lived in has
| had one. The cycle is reversed to cycle between heat and AC;
| dumping the heat to one side of the system or the other
| depending on need, as controlled by the thermostat.
|
| What is the alternative? I've seen in (new and old!) England
| they use natural-gas radiators sometimes, and have no AC, or
| window AC units. Is that it, and now areas with those are
| switching more to heatpumps? Or is it new, more efficient heat
| pumps? Or do I have a misunderstanding of the existing tech?
| tnorthcutt wrote:
| I would venture to guess that most residential heating in the
| world is provided by non-heat pump sources.
|
| In many parts of the United States, my understanding is that
| it would either be natural gas fired furnaces with forced
| air, oil fired furnaces (with forced air? not sure),
| radiators (with water heated by gas or oil fired furnaces),
| or electric resistive heating elements (e.g. baseboard
| heaters).
| Robin_Message wrote:
| UK is almost exclusively hot water radiators heated by
| natural gas boilers (or oil boilers in rural areas not on the
| gas grid).
|
| There is a push by government to switch to electric heat
| pumps driving hot water into larger, cooler radiators (as
| this is more efficient for the heat pumps), backed by a
| PS7500 grant for the pump and installation (with limited
| take-up).
| unregistereddev wrote:
| In my area in the midwest, nearly every house has a natural
| gas burning forced-air furnace for the winter and a
| standalone air conditioner for the summer.
|
| Newer heat pumps have gotten a lot better, and as a result a
| few people are starting to use them here. Even so most heat
| pumps are the more expensive type that rely on geothermal
| coils. We have extreme seasonal temperature changes that make
| older heat pumps impractical. For about two weeks each
| winter, our overnight lows are around -20F (-29C) and we
| often see wind chills around -40. Summer temperatures
| regularly reach 100F (38C).
| class3shock wrote:
| In the US heat pumps have only seen widespread adoption in
| the last decade or so and even then mostly in new
| construction applications. Most houses still use either
| window or central AC units and then some other mechanism for
| heating, oil or gas furnace, electric baseboard, etc.
| LeifCarrotson wrote:
| The houses I've been through in the Midwestern US typically
| have forced-air natural-gas furnaces and cooling-only non-
| reversible central AC. Burning natural gas is way cheaper
| (ignoring externalities) to generate heat than even a heat
| pump, and can be easily scaled up to provide tons of heat on
| really cold winter days. Plus, modern heat pumps are high
| precision, complicated, expensive tech, a furnace is old
| tech: just a burner and a blower.
|
| My natural gas cost is $0.82/CCF or $0.028/kWh. Electric is
| $0.161/kWh. That means a heat pump needs to be 575% efficient
| to break even on energy cost (assuming my furnace is 100%
| efficient, it's not, a lot of heat goes out the chimney).
|
| People only get heat pumps here if they're carbon-conscious.
| the__alchemist wrote:
| Thanks for the info on this! It sounds like my experience has
| been biased by coincidence. Ie, I've only lived in a house
| that was wired for gas once! (Northern VA). My childhood home
| (Also northern VA), both places in North Carolina, and
| Florida have all been heat-pump based, with no gas line.
|
| My apartment in the UK was even weirder: It had something
| called a "Economy 10", with an electric heater (resistance?)
| in a concrete slab under the floors that would run at night,
| then release heat slowly throughout the day. (No A/C)
| jjeaff wrote:
| I would be interested to see the math on replacing a cheap unit
| every 10 years versus an expensive unit that lasts 30. A few
| years ago, we replaced our 30 year old Carrier system with a
| new heat pump system that was relatively inexpensive. But
| here's the thing, the old system was not nearly as efficient
| from the beginning and it was much less efficient 30 years
| later. I'm not sure how much room for improvement there is with
| the new heat pump systems in regards to efficiency, but if the
| advances are significant every 10 years or so, it may net out
| to a positive.
| class3shock wrote:
| Individually that's one way to look at it that makes sense.
| On mass scale though, if in 10 years someone can make one
| that's 50% better, it still behooves the world for the the
| units of today to last 50 years because even by then you
| won't have manufactured enough for everyone to have heat
| pump, let alone the most current one. Another way to think
| about it is imagine if instead of your unit dying in 10 years
| when you got a more efficient one you sold it to someone who
| didn't have one yet.
|
| In general though, it's more the idealogy that gets me. It
| would be so easy to do a little more work to make things
| repairable, to use common parts, and ultimately create units
| that could last decades instead of lasting until an electric
| board has a short from dust or a pump predictably dies just
| outside of warranty, taking out an otherwise perfectly
| functional unit. It's just not viewed as the most profitable
| way, atleast not with how most people buy things today.
|
| I think it could be profitable though, if you get enough
| people that can do the math and realize that over a lifetime
| it's cheaper than I think you could make that work.
| Additionally, it's not just about the cost over time but what
| happens when failures inevitably happen. Try having a repair
| done on any appliance today under warranty. First you have to
| go through the company and you get whoever they send and then
| you need their parts, if they are still available, which
| often they aren't. If the documentation on how to
| repair/maintain is opensource then you could potentially get
| anyone to fix it and if the components are COTS were possible
| then you aren't screwed when your 5 year old heat pump has an
| electrical failure because you can just but a new board
| (raspberry pi lets say) flash the software and install it.
|
| I'm simplifying but I think you get the idea.
| danans wrote:
| > That is to say, as soon as something goes wrong with them,
| they are garbage.
|
| Can you unpack what you mean by this? Standard A/C's can be
| repaired - fans can be replaced, as can compressor motors.
| Also, better and more efficient heat pumps can be more
| sensitive to maintenance (or lack thereof), because they often
| achieve that efficiency through finer control of mechanical
| components or lower resistance components.
|
| IMO, a bigger factor in the longevity of traditional A/Cs is
| that they tend to have single-stage compressors that are over-
| sized for their loads most of the year, resulting in short-
| cycling and therefore shorter equipment life.
| pstrateman wrote:
| It's quite often cheaper to purchase a completely new unit
| than to fix an old unit.
|
| Factory supplied parts disappear fairly rapidly after
| products are end-of-life and labor to repair can be quite
| expensive.
| semi-extrinsic wrote:
| This is true.
|
| We have a decent-quality Mitsubishi unit that's 7 years
| now. Last year, one of the main boards died. Living in a
| country with strong consumer protection, I was able to
| argue my way into having Mitsubishi cover the cost of a new
| board, I just had to cover labour.
|
| If I'd had to cover all the cost, it would have been more
| than 40% of the cost of a new unit, and then you start
| asking yourself if it's worth it.
|
| Even though the marginal cost of the main board is likely
| below $50, the replacement ones sell for close to $500.
| class3shock wrote:
| I will add to this that in the USA Mitsuibishi is one of
| the highest quality ones you can get with the longest
| warranty (10 years last I looked).
| class3shock wrote:
| Just because something "can" be repaired doesn't mean it
| makes sense to. With most appliances if you are going to hire
| something to fix it outside of warranty it will cost hundreds
| of dollars at a minimum and you are often not guaranteed a
| repair will work. Even if it is in warranty, often a
| replacement part will be needed that is not available or is
| not economical to have a person install versus replacing the
| whole unit and the company will just scrap the whole thing
| and give you a replacement (after you've spent hours on phone
| calls, emails and talking to technicians).
|
| The most egregious example of this I will highlight is
| electronics. Ask any manufacturer to provide a replacement
| board for an otherwise functional heat pump, air conditioner,
| etc. They likely won't have one. And even if they do, are you
| now going to hire someone to replace it? Do it yourself? If
| you aren't mechanically inclined its option one which can be
| hundreds of dollars and if its option two you will now be
| doing it likely with no or poor documentation spending how
| much of your time?
|
| Heat pumps are no more sensitive to maintenance than air
| conditioners (besides the use of longer hoses for the
| refrigerant movement giving more opportunities to generate
| leaks). Or atleast their nature doesn't mean they inherently
| need to be (maybe that's the better way to put it).
| Compressors, fans, radiators, inverters, these are things
| that have been made for decades and if you walk into any
| commercial manufacturing space you'll find examples last for
| decades. That level of quality just isn't offered for homes.
|
| You are absolutely correct that over-specifying heat pumps is
| also a big issue. That's kinda've a whole nother topic though
| that we could get into along with energy modeling,
| regualtions/practices, etc.
| tsss wrote:
| > If I save 60% on energy for heating every year but then
| require all the energy needed to build a new heat pump every
| 5-10 what am I really doing?
|
| Activism.
| turtlebits wrote:
| Where are you seeing this? Mini splits have been in use for a
| long time and just about all cheap brands are rebadged Gree and
| Midea, which are reliable and in use all over Asia.
|
| IMO, the problem is that HVAC companies in the US overcharge so
| much for install/labor that homeowners are more inclined to
| replace them. They won't touch mini split brands that they
| don't install (and generally only install expensive brands)
| Cort3z wrote:
| I recently had to get a replacement heat pump. In the process I
| discovered that the EU has a database of energy ratings for
| almost (actually?) all electric appliances sold in the eu. This
| includes heat pumps.
|
| I scraped the heat pump data and am the proud owner of 100% of
| this information. What I found is that some of the available data
| is inaccurate and much of the energy ratings (A-G character
| rating) is inconsistent with the performance of the device,
| probably due to changing standards over the years. It's nice to
| see initiatives like this which hopefully will provide better and
| more normalized data.
|
| As a side note. Air-to-air heat pumps have, as most people know,
| two parts to it. The indoor unit, and the outdoor unit. Many
| models can be used interchangeably, so the domain of heat pumps
| is a bit more complicated than I first anticipated.
| jonasdegendt wrote:
| To my knowledge, the A-G energy rating is a rolling standard.
| It gets a little bit tougher to make A grade every year.
|
| NCAP works the same way.
| Cort3z wrote:
| Indeed. The data available includes most of the things you
| would expect, but some of it is just wrong. I'm only at my
| computer now, so don't have a concrete example, but some
| models had vastly higher values for some fields than is
| possible.
| qsdf38100 wrote:
| Are all the compared heat pumps working at the same temperature
| levels? Otherwise, the COP isn't a good comparison metric, as
| even for an ideal heat pump with a COP = 1 / carnot_efficiency,
| it depends on the temperatures.
|
| For instance, a heat pump lifting heat from 20degC to 100degC
| with a COP of "only" 2 is excellent, whereas lifting heat from
| 20degC to 30degC with a cop of 3 is not impressive.
| tgtweak wrote:
| How is the heat output calculated and validated?
| twic wrote:
| Heat pumps are obviously great in many ways. But fitting one is a
| big deal - they are quite expensive, they take a lot of work to
| fit, really require extensive additional insulation, and there
| are all sorts of caveats to them that mean they aren't a
| straightforward replacement for a boiler.
|
| So i'm slightly mystified that we basically don't hear anything
| about fitting drainwater heat recovery [1], in which the lukewarm
| drain water from your shower is used to pre-warm the incoming
| cold water. It's extremely simple, pretty cheap, simple to fit,
| and can recover ~50% of the waste heat, of something which is
| tens of percent of the energy consumption of a household.
|
| By all means, get a heat pump. But get a heat exchanger on your
| shower first!
|
| [1] https://www.energy.gov/energysaver/drain-water-heat-recovery
| SomaticPirate wrote:
| For most single family US homes (which are single story) this
| would likely be a nightmare to install and maintain.
|
| Definitely a cool idea but a leak or any maintenance might
| quickly undercut the cost savings
| PaulDavisThe1st wrote:
| Just as an FYI:
|
| > Information obtained from the US Census Bureau's Survey of
| Construction (SOC) and tabulated by NAHB, shows that the
| rising trend of single-story homes reversed in 2021. The
| share of single-story homes decreased in 2021 and the share
| of two or more stories homes started was greater than one
| story homes. This is in line with recent NAHB analysis of new
| single-family home size trends.
|
| https://eyeonhousing.org/2022/07/share-of-two-or-more-
| storie...
| Wohlf wrote:
| Speaking of heat pumps and water heat, I installed both a heat
| pump and hybrid water heater to save on electricity. The water
| heater doesn't seem to have made much of a difference in my
| electrical bill, my guess is the problem is peak demand so I
| should have gotten a much bigger tank than before. Ambient
| garage temperature may also be an issue but it exhausts outside
| and the garage is insulated so it generally stays above 55
| degrees.
| cogman10 wrote:
| Make sure you are in energy saving mode. The default for
| these systems is to try and do quick recovery which likely
| isn't what you want.
| bluGill wrote:
| While those save money, most people don't really use a lot of
| hot water and so the amount they can save is limited.
| alostpuppy wrote:
| Ah. I installed one in a uninsulated garage and it was really
| a big savings. It's basically a free ac for whatever space
| it's installed in
| uconnectlol wrote:
| they also aren't very hot and wont work in northern cities, but
| people will install them there anyway. "boiler" - is that
| jargon for multiple kinds of heating units or actually just
| boilers?
| twic wrote:
| By boiler i mean the big box on the wall in the kitchen which
| burns natural gas to heat water. This may be a UK specific
| usage.
| foresto wrote:
| I think this is known as a tankless water heater in the US.
| (Tankless because you said it's on the wall.)
| komadori wrote:
| Boilers in the UK are usually mounted on the inside of an
| exterior wall to provide for venting exhaust gases
| outside. They may provide hot water on-demand without a
| tank (combi boiler) or fill a hot water cylinder on a
| schedule (system boiler) depending on type. Heating is
| typically provided by the boiler pumping hot water
| through a circuit of wall-mounted radiators regulated by
| TRVs (Thermostatic Radiator Valves).
| doctorhandshake wrote:
| Are you saying heat pumps won't work in cold climates? That
| hasn't been true in some time.
| https://www.greenbuildingadvisor.com/article/heat-pumps-
| for-...
| bluGill wrote:
| Heat pumps work down to -25C. Cold climates get colder than
| that. Sure most cold climates are typically above that, but
| it only takes one night every 10 years to hit those
| temperatures and a heat pump alone does not work. You need
| a backup. Of cousre once we have a backup we can ask if it
| is cost effect - heat pumps get less efficient as
| temperatures go down - when you need the most heat, so it
| may be most cost effective to install a heat pump that
| doesn't even work to that cold (perhaps it does but is
| under sized?) and just use backup heat when it is cold.
| cogman10 wrote:
| > But fitting one is a big deal - they are quite expensive,
| they take a lot of work to fit, really require extensive
| additional insulation
|
| I think this somewhat overblows the complexity of a heat pump.
|
| They are simply Air conditioners that can be ran in reverse.
| One valve is the difference between a heat pump and AC. Why
| they are so expensive is really just price gouging because they
| aren't as common.
|
| If you are in a home with forced air AC then installing a
| heatpump system couldn't be simpler and should be something you
| consider when updating your AC system. It's really just a
| matter of updating the compressor and maybe adding some smarts
| to avoid condensation. In fact, it's shocking to me that AC ->
| heatpump conversion kits haven't hit the market.
|
| > So i'm slightly mystified that we basically don't hear
| anything about fitting drainwater heat recovery [1], in which
| the lukewarm drain water from your shower is used to pre-warm
| the incoming cold water. It's extremely simple, pretty cheap,
| simple to fit, and can recover ~50% of the waste heat, of
| something which is tens of percent of the energy consumption of
| a household.
|
| Really interesting idea, but I assume you have to rip up the
| shower to accomplish this right? Also, I'm guessing clogged
| wastewater piping might be an issue right? That said, that'd be
| easily overcome by just running the lines side by side with
| maybe a simple copper connector for heat exchange.
| bluGill wrote:
| What is mystifying to me is why governments allow air
| conditioners without that reversing valve to be installed. A
| simple change, and the more people installing a heat pump the
| cheaper those valves get.
| braiamp wrote:
| I see tables, I am exited. But I can't make sense of what
| anything is? I know COP, but what is Training, what is Source?
| MID seems to be a kind of sensor? Some of the table headers have
| a tool tip explaining things, but are the ones that aren't the
| most needed. Also, some about page about what the table
| aggregates and how it gets there? Seems to be some kind of
| aggregator for information gathered from an appliances called
| "emonHub" which is a rPi that gathers data from an assortment of
| other devices. There are some jargon that you have to parse,
| ("supply" means the electric cables that "supply" your heat pump)
| to understand what's going on.
|
| The best guide I could find is buried all the way down of the
| documentation
| https://docs.openenergymonitor.org/applications/heatpump.htm...
|
| That's it.
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