[HN Gopher] Harnessing America's Heat Pump Moment
___________________________________________________________________
Harnessing America's Heat Pump Moment
Author : ssuds
Score : 39 points
Date : 2025-10-24 20:05 UTC (2 hours ago)
(HTM) web link (www.heatpumped.org)
(TXT) w3m dump (www.heatpumped.org)
| themafia wrote:
| They don't provide heat below freezing unless you get a
| specialized model. Even then their ability to provide heat
| reduces the colder it gets outside. It's still recommended to
| have a backup should you live in an area where this could happen.
|
| It's great on paper. It has obvious problems in practice.
| micromacrofoot wrote:
| This is outdatated nonsense, I had my system installed 10 years
| ago and it works down to -15F... even the cheap $1k systems on
| Amazon work below freezing now
|
| Like any piece of equipment, just check the specs before you
| buy...
| happytoexplain wrote:
| It's semi-true even with modern systems and shouldn't be
| outright dismissed as "nonsense".
|
| A normal person is scared of the prospect of _losing heating
| when it 's most needed_. -15F accounts for many places in the
| US, but many others, not so much. Even New Jersey, which we
| don't think of as the frigid North, _can theoretically_ drop
| below that number, and nobody wants "almost always" when it
| comes to life-giving heat in the coldest winter.
| micromacrofoot wrote:
| I live north of New Jersey by 300 miles and have only used
| a heat pump for winter heating for 10 years
| quickthrowman wrote:
| What's the COP at -15F? It's probably close to 1, which means
| you're paying for resistive heat which happens to be the most
| expensive possible way to heat something up.
| RealityVoid wrote:
| Just checked the spec of mine at -10degC. It's a bit over
| 3.
| quickthrowman wrote:
| That's +15F, what's the COP at -26C?
| RealityVoid wrote:
| Whoops, my bad when doing the transformation. It won't
| work that low, only down to 20degC and at that point it
| probably approaches 1. Lucky me, the temps never dropped
| to under 19degC in the last 20 years in my area. So I'm
| probably going to be fine.
| SigmundA wrote:
| A Mitsubishi Hyper-heat MXZ-4C36NAHZ for instance has a COP
| of 2.12 at -13F outdoor temp and 70F indoor temp.
| quickthrowman wrote:
| That's actually a lot better than I expected, thanks!
| micromacrofoot wrote:
| Yeah most places aren't consistently -15F, not going to be
| a dealbreaker for a week.
|
| If you live in Minnesota stick with gas, we'll be ok. The
| majority of the population will never hit -15F.
| Centigonal wrote:
| Cold climate heat pumps have improved a lot, even in the last
| 10 years. Modern models can maintain comfortable temperatures
| down to -15F (-26C).
|
| Lots of happy customers in this reddit thread:
| https://www.reddit.com/r/heatpumps/comments/146jg7k/cold_cli...
| themafia wrote:
| > I've tested it down to around -5 degrees (f), and it was
| 100% able to keep the house above 63 degree (f).
|
| Some customers will accept that. Most will not. Reddit is not
| a particularly representative sample of the entire market.
| hitarpetar wrote:
| ok, Reddit is not representative. what qualifies you to
| speak for what customers will accept?
| themafia wrote:
| I spent 5 years installing and maintaining A/C equipment
| for residences and a few small commercial locations.
| christophilus wrote:
| 63 when it's -5 out seems totally fine. More than fine for
| much of the US.
| nsxwolf wrote:
| "Paid more, and now we are cold". This is not my
| preferred version of the 21st century.
| VWWHFSfQ wrote:
| Maybe totally fine for you. But that will not be "totally
| fine" for much of the US when they are expecting to keep
| their house at 72 degrees and the new technology they got
| talked into can't do it.
|
| The tech has limits and cold weather states can't avoid
| that or the reputation will get really bad and the tech
| will fail.
| micromacrofoot wrote:
| I'm not sure if you've lived in prolonged -15F areas, but
| many conventional heating systems struggle too...
| especially in poorly insulated houses. People often have
| wood stoves or other ways to compensate.
| maxerickson wrote:
| If you read just a smidge of the context, it's a sizing
| issue, not a capability issue.
| nsxwolf wrote:
| This would not work in Chicago.
| pessimizer wrote:
| Chicago days under -15degF since 2015: Jan
| 18, 2016 -21degF Coldest day of that winter Dec 19,
| 2016 -21degF Early-season Arctic outbreak Dec 27,
| 2017 -19degF Part of a prolonged late-December cold wave
| Jan 2, 2018 -23degF Deep freeze to start the year
| Jan 30, 2019 -30degF Coldest Chicago temp since 1985;
| "Polar Vortex" event Feb 14, 2020 -18degF Valentine's
| Day Arctic blast Feb 7, 2021 -21degF Mid-winter cold
| snap Dec 23, 2022 -23degF Pre-Christmas Arctic front
| Feb 3, 2023 -17degF Last occurrence to date
|
| So basically every year.
|
| edit: downvoted for noticing that it is cold.
| arrowleaf wrote:
| The physics of heat pumps disagrees with you. The freezing
| point of water has no bearing on at what point they become less
| effective.
| themafia wrote:
| Heat pumps lose efficiency as it gets colder. There are no
| laws of physics which contradict this.
| AnthonyMouse wrote:
| The relevant laws of physics operate in Kelvin. 60degF is
| 288 K. -20degF is 244 K. These are not that far apart.
| SigmundA wrote:
| Not exactly true, one of the main issues with heat pumps in
| cold weather is the outside coil freezing up with ice
| blocking airflow due to them being below the freezing point
| of water.
|
| This is actually why older heat pumps became less effective
| around 40F because the coils would start to hit 32F since
| they are attempting to pull heat from the warmer outside air
| and are therefore colder than the outside air.
|
| There are various solutions to this problem, the standard way
| is to run it in reverse as a air conditioner for a short
| period if it detects the situation to defrost the coils and
| if the system has resistive heat strips it uses those to warm
| the air that is being cooled. This obviously reduces the
| efficiency of the system the more it has to defrost and may
| not be very comfortable to the users.
|
| Cold weather heat pumps work better in drier climates due to
| this as well because the lower the outside humidity the
| slower frost will form on the outside coils.
|
| Some cool weather heat pumps will have two compressor units
| and fans and alternate between them with one defrosting the
| other, there are many other tricks they are using to prevent
| frost buildup and continue working above COP 1 far below
| freezing.
| stevemk14ebr wrote:
| Even at 0F most modern heat pumps produce heat at a COP greater
| than 2. This means you get twice the rate of heat generation
| than a typical electric space heater. You are out of date, and
| wrong.
| discoutdynamite wrote:
| Yep, you get what you pay for. They've started fielding systems
| that will handle extremes much better, but you dont get that
| kind of performance without tradeoffs. cascade systems, 200psi
| r600, 450psi CO2, refrigeration systems are an engineering game
| irl. They require much more experience to design, setup, and
| charge correctly. The biggest issue I have with heat pumps for
| life support heating/cooling, is they have so many single
| points of failure its scary. Compressors can and will die if
| anything else in the system goes too far out of the intended
| cycle. Extreme weather moments or natural disasters can
| physically break condensors, evaporators, and lines. Electrical
| surges can and will fry computers, inverters, and controllers.
| And almost none of those can be serviced on your own.
|
| t. certified
| RealityVoid wrote:
| That is true only for air heat source. And even those work in
| below freezing (the one I have works down to -20degC) but as
| you say... with diminishing returns. Still, checking the
| technical spec, it says that at -15 degC it heats up a tad
| under 3x as much energy it uses. Pretty good I would say!
| thinkcontext wrote:
| You see this opinion a lot in the US, probably a result of Fox
| and its ilk. As the article mentions, somehow Nordic countries
| and Canada manage to use them. There's been good uptake in
| places like Maine which is good news.
|
| Its true retrofits are a tough sell and natural gas is really
| cheap here. It would help if the US took insulation more
| seriously. But for someone with oil or electric resistance its
| definitely a big win.
| joshvm wrote:
| Below freezing is a concern that everyone has in Northern
| Europe, particularly Scandinavia which has very high per-capita
| adoption. The units might be harder to find in the US, but they
| definitely exist.
|
| If you can afford it, and have the land access, you could
| install a ground-source pump which should benefit from more
| stable temperatures. As with all heating/cooling, these systems
| work best if your house is well insulated. That's a much bigger
| problem in the UK, and I imagine the US too, especially in
| places where solar gain requires a huge amount of A/C usage.
|
| [1] https://www.cell.com/joule/fulltext/S2542-4351(23)00351-3
| bluGill wrote:
| Northern Europe tends to have a mild climate in the places
| where people live. The Northern US is significantly south,
| yet gets significantly colder winters. There are places in
| Europe that get worse than the Northern US - but they are
| places where few people live and so not normally what you are
| talking about when talking about Europe.
|
| Though good heat pumps are hard to find in the northern US.
| Most installers only know of gas furnace + A/C, and don't
| even try to install anything else. As you get farther south
| in the US heat pumps become common, but there it rarely gets
| much below freezing and so they don't need backup heating
| systems at all.
| AnthonyMouse wrote:
| The backup system can be resistive heaters which are
| inexpensive and low maintenance, and their lower efficiency
| isn't that big a deal when you're only using them 2% of the
| time.
| galoisscobi wrote:
| > we're waiting on people
|
| Right on. I have a heat pump water heater and a heat pump heating
| system in my HVAC. Getting those installed felt like swimming
| upstream. Most contractors would try to dissuade me from them.
|
| Luckily, I found a contractor who was skilled and knowledgeable
| about heat pumps and rebates (back when govt thought climate
| change was real). Very happy with my heat pump tech.
| jbm wrote:
| I had a similar problem too. Was unable to find anyone who was
| willing to quote me on a heatpump when I was installing my air
| conditioner. I assume it will be better in 5-10 years when I
| have to replace them.
| bamboozled wrote:
| We have the same setup , we love it.
| brendoelfrendo wrote:
| I guess I lucked out; our house had a (very old) whole-home
| (that is, ducted) heat pump system for heating and cooling when
| we moved in. When it was time to replace, our local contractor
| knew exactly what we needed. They even do mini-splits, had we
| wanted one.
| Glyptodon wrote:
| Do newer ones somehow not need ducts?
|
| Edit: (or so you mean mini splits?)
| brendoelfrendo wrote:
| No, no ductless magic without mini splits. I feel like a
| lot of people refer to heat pump systems interchangeably
| with ductless mini splits, so I wanted to clarify that.
| Maybe that's just an issue with the people I speak with,
| though.
| ortusdux wrote:
| I ended up self-installing my HP-WH. Professionals either tried
| to talk me out of it like you described, or charged a premium
| for the upgrade. My county has a rebate that allows for self-
| installs. It was rather straight forward and ended up being
| ~$700 in the end. The old unit I tore out took an extra
| $350/year in electricity, so I've already broken even.
| darth_avocado wrote:
| I'm in California, I have two heat pumps installed. I can sum
| up the problems as follows:
|
| 1. They are EXPENSIVE. The equipment itself isn't that
| expensive tbh but installation is pretty expensive. The
| government subsidies have made sure that the contractors jack
| up their own prices by as much.
|
| 2. I end up paying more in utilities because electricity is
| very expensive and heat pumps aren't nearly as good at heating
| in the winters as old fashioned gas furnaces when it comes to
| the cost.
|
| I made the massive investment because I could and I eventually
| want my house to run completely on rooftop solar as a way to
| reduce my carbon footprint. But the cost is nowhere near mass
| market adoption price range.
| micromacrofoot wrote:
| Our local installers seem to be taking advantage of the moment
| quite a bit, install costs are have skyrocketed over the past
| decade... double what I paid when the market started heating up.
| But at least the techs seem more knowledgeable, when I first had
| my system installed it seemed like they had no clue how they even
| worked.
| andrewvc wrote:
| One other challenge is for existing homes a water heater may only
| have a gas line running to it. Want a heat pump hot water heater?
| Hiring the electrician alone, not to mention potentially ripping
| up walls will ruin any economic advantage.
| atrus wrote:
| A possible challenge, yes, but there exist 1500w, standard
| outlet hpwh, and it's a lot less common to not have _any_ power
| near a water heater.
| quickthrowman wrote:
| A 1500W electric water heater would be painful to use in a
| home. A typical 30-60 gallon EWH is 6kW.
|
| And for the record, every single natural gas water heater is
| connected to 120V power for the ignition circuit.
| SigmundA wrote:
| a 1500W heat pump water heater with a COP around 3 will put
| 5500 watts of heat into the water.
|
| My Rheem hybrid 220v heat pump water heater only has a 500w
| compressor but puts 1500-2000 watts of heat into the water
| pulling it from the hot garage.
|
| I have the choice to run it in high demand mode which will
| run both the heat pump and electric 4500w element for
| around 6kw of heat into the water if I need fast recovery.
| harshreality wrote:
| I think this is right...
|
| kwatts_effective [kJ/s] * heating_time_minutes [min] * 60
| [s/min] * COP = 4.184 [kJ/kg/K] * (T1-T0) [K] *
| gallon_capacity [gal] * 3.785 [L/gal] * 1 [kg/L]
|
| 6.6 kW, for... COP 4, T1-T0 = 30 [K] (lower value for warm
| climate), allowable 30 minute heating time, 50 gallon
| capacity. A cold climate could double that power
| requirement, or alternatively double the heating time.
| maxerickson wrote:
| It's not uncommon for a gas heater to have an always on
| pilot.
| underbluewaters wrote:
| This was a major barrier for me. I had to replace an existing
| natural, tanked gas water heater. Ultimately I just bought a
| $750 replacement because I could easily swap it out myself.
| Installing a heat pump would have involved an electrician to
| install a new circuit, and possibly other changes. While there
| were some 120v models available locally, they all had pretty
| bad reviews. So I would have paid a couple thousand dollars
| more. Maybe I could break even over 10 years paying less for
| gas but that seemed like a poor use of funds.
| nsxwolf wrote:
| When I needed a new air conditioner I looked into heat pumps. 3x
| the price.
| wffurr wrote:
| That's crazy. It's a reversing valve.
|
| But you might also be comparing multi-stage variable load DC
| heat pumps with single stage air conditioners and not an
| actually equivalent air conditioner.
| jjtheblunt wrote:
| or local sellers are incentivized profitably to push old
| technology air conditioners?
| prlambert wrote:
| That seems really weird, the only real difference is a
| reversing valve that costs a couple bucks. A heat pump is an
| AC, it just can be run backwards to produce heating as well. In
| cooling it's literally the same thing.
| bluGill wrote:
| I know, but I don't make the price lists.
| thinkcontext wrote:
| I'm no expert but the difference in the real world is more
| than that (though am doubtful about 3x the price) . The
| delta-T between heating and cooling is significantly greater
| in most places so you need a bigger system. You also need
| things like the ability to de-ice.
| supportengineer wrote:
| That's the _upfront_ price. What about the total cost of
| ownership (TCO)?
| mithr wrote:
| Electricity costs are a big factor in this, imo.
|
| Rates for my northeast town increased by ~25% in 2024 and are
| going up by another ~10% this year. It's a hard sell to spend a
| large amount of up-front money (even after rebates, which
| _decreased_ this year) to convert to a system that will cost you
| more than you pay today, and may not work as well in cold weather
| (every heat pump company I talked to suggested keeping my
| existing gas heating in place and automatically switching to it
| when it gets cold enough).
|
| I was also told that the electrical grid in my area is having
| difficulty keeping up with the push towards heat pumps, which
| increase load exactly on the coldest nights of the year, when you
| need heating most.
| VWWHFSfQ wrote:
| A heat pump just makes no sense whatsoever for me in my
| northeast town. The electric bill alone would outpace the old
| propane bill, not to mention installation.
|
| And it won't even work during some of the coldest winter weeks
| when you _really_ need it to work.
|
| Maybe I would consider it if I was in, like, Nevada or
| somewhere.
| blahedo wrote:
| People are reluctant to install them because they _don 't work_
| as well as the good old boilers we'd be replacing. I'm not saying
| they can't, and I'm not saying that there are zero models out
| there that work. But in practice, a lot of us that have
| interacted with heat pumps have the specific experience that they
| get anemic as the temperature goes down and eventually become
| unable to do much of anything.
|
| I live in the mid-Atlantic (US) climate zone, where it's
| certainly not as cold as the north but definitely goes well below
| freezing regularly for several months of the year. The place I've
| lived for 15 years had a heat pump and a (oil) boiler with
| radiators, and when it was below 40degF (~5degC) I had to switch
| to the radiators. It's because it's old, everybody told me,
| modern heat pumps are better! So last year when both systems
| needed repairs at the same time, I not-entirely-willingly
| switched to a brand-new 2024-model heat pump. It absolutely could
| not keep up when the temperature was freezing until they came
| back and installed resistive heat strips for low temperature---
| these seem to be a fancy version of the heating elements in a
| space heater or a toaster. They do not seem to be particularly
| efficient. And to the extent that my "heat pump system" does now
| more or less keep the house adequately warm, if not as
| comfortable as the radiators always could, it's not solely due to
| the heat pump, but the other stuff they had to put in because the
| heat pump couldn't keep up.
|
| My experience is far from unique. Maybe it's that they only
| install the good ones in farther-north locations! Maybe it's that
| the good ones are just way more expensive! I'm perfectly prepared
| to believe the factual statements about the physics and the tech.
| But if we're talking about perception and "why aren't more people
| looking to install heat pumps", it's because lots of people have
| experiences like the above, and _that_ is what the industry needs
| to work on.
| lbotos wrote:
| What brand and was it sized for winter load?
|
| Im in NY, 6 heads across 3 floors with 2 heads per outdoor
| unit. 2500sf covered.
|
| Mitsubishi h2i (i think im on my phone). Get plenty warm in the
| winter as my sole heat source. I could have gotten smaller
| outdoor units and had resistive backup but I didn't want that.
| maxerickson wrote:
| How is the insulation in the house? Poor insulation and an
| undersized system will be a bad experience regardless of the
| heat source.
| baggy_trough wrote:
| It wasn't a bad experience before, but now it is, because of:
| new heat pump
| maxerickson wrote:
| Well what capacity does each system have?
|
| That they came back and added resistive heating suggests
| your contractor may not have been too worried about sizing
| the system correctly in the first place.
| prlambert wrote:
| Yes this is actually the worst - when open minded people get a
| heat pump for "the right reasons" and then have buyer's
| remorse. Completely backfires the transition. Do you have a
| ducted or ductless heat pump? Sounds like ducted, and if so
| that might be part of it too. The air cools down in the
| ductwork and if that's not accounted for - i.e. you reuse
| ductwork that was meant for a furnace - you run into issues
| like this. And you also need a cold climate heat pump.
|
| (disclosure/transparency I'm the founder of Quilt, a ductless
| heat pump manufacturer)
| WorldMaker wrote:
| The strength of your heat pump shouldn't be outside surface
| temperature, but underground aquifer temperature. Those two
| temperatures are related but not as directly as they seem. A
| good aquifer in certain cavernous regions of the US might stay
| about 55 degF year round, regardless of outside surface
| temperature. 55 degF is still below what a lot of people want
| their home to be year round so a heat pump still has to
| supplement heat somehow in winters (or radiators or what have
| you), but a "free" boost to 55 degF is still a better starting
| place than 20 or 40 degF outside temperature.
|
| I don't think latitude is a factor in how efficient a heat pump
| you can find, I think the type geography under you feet is
| (probably where "interior" regions probably have more luck than
| coastal regions), combined with how well regulated or
| unregulated your area's aquifer generally is (things like
| nearby wells and industrial water dumping will effect aquifer
| levels and temperatures). (Maybe not enough heat pump
| proponents realize that you only have good, cheap heat pumps if
| you have a powerful EPA and other Water protection groups
| fighting the good fight in your region.)
| estimator7292 wrote:
| You're talking about geothermal heat pumps which are _far_
| less common than air-to-air heat pumps because they are _far_
| more expensive.
|
| These are entirely disjoint concepts.
| jcalvinowens wrote:
| The radiators might make you feel warmer despite not actually
| making the air in the room warmer: the black body radiation
| from the big warm radiators affects your perception of warmth
| in a not insignificant way.
| estimator7292 wrote:
| Resistive heat strips are what all electric furnaces use. It's
| just a bunch of coils of nichrome heating wire. The efficiency
| of a resistive heater is basically 100%. One Watt of
| electricity in gives you one watt of heat out.
|
| The mistake people make is assuming a heat pump can do
| everything by itself anywhere in any climate. If you have cold
| winters, you need a dedicated furnace to supplement the heat
| pump.
|
| I say supplement because while an electric furnace is near 100%
| efficient at turning electricity into heat, a heat pump can be
| far more than 100% efficient. And that's the crucial detail: a
| heat pump _can_ give you more heat per Watt than a resistive
| heater when outside temperatures are warm enough.
| amarant wrote:
| This is such a weird tale to hear. I heat my 2 story 147m2
| house in Sweden with a single heat pump and it's downright cosy
| down to -10C. I have noticed that my office, which is located
| at the furthest possible place from the heatpump, tends to get
| a bit chilly when outdoors temperatures fall below -10degc.
| usually a blanket is enough to keep me toasty, but on the rare
| occasion that it gets real cold (below about -15degc), I have a
| fireplace to save the day. That fireplace actually gets used
| more for the cozyness of a fire than it does for actual need of
| heating, but it does help on the worst days of Scandinavian
| winter.
|
| All this to say: if your pump can't handle +5degc, I wonder if
| you got scammed or if there are other factors at play? Is your
| house insulated at all? Do you keep your windows open
| throughout winter? Your experience is so different from mine
| it's hard to believe we're even talking about the same
| technology!
| ssuds wrote:
| I just wrote a big thread yesterday responding to someone with
| similar concerns to yours (https://bsky.app/profile/shreyassudh
| akar.com/post/3m3w3nra2h...). Copying it here if it's helpful
| to other folks. FWIW, the challenges you are facing seem to be
| grounded in bad design and application, which happens more than
| it should and really sucks. We need to move the bar much higher
| for the contractors installing heat pumps. Here's what I wrote
| on that thread:
|
| This is why contractor & homeowner education are so so so
| important to get this energy transition right! I always hate to
| see reviews like this from folks that have installed a heat
| pump.
|
| It's almost always a combo of poorly communicated expectations
| & installer issues.
|
| A few thoughts...
|
| 1) "Air doesn't come out hot" is a common complaint. It's by
| design! You don't need scalding hot air to have a comfortable
| space. If you're targeting a 70 degree setpoint, even 80 degree
| air will get you there eventually. Heat pumps work best when
| you let them run - they soak the space with heat.
|
| Your furniture, walls, floors all equalize in temp and radiate
| heat. A totally different form of comfort than standing in
| front of a vent that blows hot air at you for 5 minutes and
| then shuts off!
|
| 2) AC doesn't reduce humidity as well. Unfortunately, this is a
| classic problem with oversized heat pumps. The key to
| dehumidification is runtime. A well sized system will run for
| longer, which will pull the humidity out of the space. If the
| system is too big, it'll cycle on and off & not dehumidify.
|
| Your contractor should be do load sizing calculations to
| determine the size of your heat pump, not using rules of thumb
| or matching the size of the existing equipment! The very best
| contractors use performance based load calcs, where they look
| at your past energy bills to size your new system.
|
| 3) Supplemental heat runs a lot - this SUCKS. Electric
| resistance heat is really expensive to run. It really should be
| something that comes on for emergencies, if ever. Definitely
| not regularly.
|
| Many contractors set the temperature where the supplemental
| heat kicks on way too high. You could be running the heat pump
| (which is way more efficient) to a much lower temperature, but
| it'll switch to expensive aux heat instead. Fortunately, the
| fix to this is simple - just a thermostat setting.
|
| In other cases, they'll install a cheaper mild climate heat
| pump in a truly cold climate. This might save money up front,
| but it'll kill you in operating costs when you're paying 4x as
| much as you could be in the middle of winter to heat your home.
| The lowest bid could cost you in the long run!
|
| PS - this homeowner later chimed in that swapping the
| thermostat helped reduce their electricity bill roughly
| $30/month! A lot of heat pump issues actually boil down to a
| poorly configured system. Choosing the right contractor is
| probably the single most important decision you'll make when
| you get a heat pump installed.
| mrguyorama wrote:
| Well
|
| Mitsubishi sells heat pumps that produce 14kw of heat output
| all the way down to 5f at a COP of 2.3.
|
| Resistive heat has a COP of 1, by definition.
|
| Do you know the size of your oil burner? It's likely over 20kw
| output.
|
| It's not that pumping heat cannot work sufficiently at cold
| temperatures, it's that you are expecting the electric car
| rated 100 horsepower to go as fast as the gas car rated at 300
| horsepower.
|
| An oil burner sized to the same output as the heat pump _also_
| would not keep up.
|
| If you installed two of those Mitsubishi heat pumps (which
| would require two independent 240v circuits), you would be at
| 28kw output and would not need resistive heat strips. These
| units also claim 75% rated capacity at -13f so that would be
| about 21kw of heat output even when very very cold.
|
| If your resistive heat strips activate at any point other than
| extreme weather events or emergencies, your "system" is not
| sized properly. They are a massive waste of power and money.
|
| A big part of the problem is that the contractors who are
| essentially the point of sale for these systems are just
| obscenely dumb about them. They will sell you utterly
| undersized units or sell units that aren't rated for cold, as
| well as just install things so poorly that they drain
| condensate into your walls and cause mold issues. They had
| similar problems with Oil burners, but at least those they
| tended to upsell bigger systems so their ignorance didn't
| matter. They seem very bad at doing the planning or design
| required to actually spec out a system, so you have to be your
| own engineer.
|
| >and that is what the industry needs to work on.
|
| I don't know how the industry is supposed to force contractors
| to read their very very clear documentation, or follow the very
| clear instructions (of boiler manufacturers no less) of "You
| must measure heat load to accurately size a heat appliance".
| Glyptodon wrote:
| I live in a heat pump only house and the only thing I don't
| really love are mid summer electric bills, but I think that'd
| basically be the same with a dedicated AC. In my climate heat is
| more nice than complete necessity and usually only spikes bills
| if there are true hard freezes.
|
| I will say, they seem to have gotten more expensive. It took
| about $10k to replace ours (it was over 20 years old and
| replacing coolant+fixing was quoted at nearly half that). Even
| though research suggested it could be more like a $6.5 to $7.5k
| cost, it was hard to even get people quoting in a timely manner,
| let alone getting any kind of a deal.
| prlambert wrote:
| Cool to see a Heat Pump article near the top of HN! I'm the
| founder/CEO of Quilt (https://www.quilt.com/), which is mentioned
| in the article, and a decade+ daily reader of this fine site. At
| Quilt we've run the Nest playbook for ductless heat pumps as our
| first product. The plan is to do what Tesla did for automotive to
| the built environment infrastructure category (HVAC, plumbing,
| etc) and create the first major American manufacturer in a
| ~century.
|
| The article has bullet #1 in problems to solve as "Contractors
| who default to what they know." This was one of my founding
| hypotheses to and it turns out I was wrong, this was the hardest
| won learning yet at Quilt. We originally were fully vertically
| integrated and had our own installation force because of this
| reason - we wanted to solve all the big problems, thought
| contractors were one of them, and so had to become a contractor.
| But we quickly saw we were getting in the way of our own mission
| to accelerate the energy transition (because we had far far more
| demand than we could scale operations to reach it). So in March
| we (initially cautiously) switched partnering with existing
| contractors and I have been _delighted_ by the industry
| reception. There are so so many existing contractors who want
| modern tech and see working with us as a breath of fresh air. I
| definitely sold them short and in retrospect it was naive and
| even a little elitist.
|
| Happy to answer anything more. Also I'd be remiss if I didn't
| mention that we're growing super fast and just posted an Embedded
| Software Engineer role: https://job-
| boards.greenhouse.io/quilt/jobs/4952684007 :)
| ssuds wrote:
| Hey Paul! Good to see ya on here. I'm in a Facebook group of
| small HVAC contractors, and recently there was a conversation
| about who is installing heat pumps vs traditional ACs and
| furnaces. I was thrilled to see that most were saying that they
| are moving a lot of their business toward heat pumps. Of
| course, there were a few that were stuck in their ways and were
| "gas or die" type people, but it's exciting to see the ship
| slowly starting to turn. There are more and more heat pump
| forward contractors coming online every day, and it's great
| that we can team up with folks like you pushing the hardware
| forward. There is so much work to deploy these systems, and
| winning is going to look like all of us working together!
| commandersaki wrote:
| Is Heat Pump the same as what Australian's would call a Split
| System?
| ssuds wrote:
| Yes! Also often referred to as "Reverse Cycle Air Conditioning"
| in Australia
| estimator7292 wrote:
| Split system is a common term that covers both heat pumps and
| traditional AC systems. It has to do with the physical setup,
| not the theory of operation.
|
| A heat pump specifically is an AC system that can run in
| reverse: moving heat from outside to inside.
| bluGill wrote:
| When I replaced my furnace a couple years back I asked for a heat
| pump - a previous house had it and it worked great. Turns out my
| contractor didn't ask the right questions and so mine only works
| to 25F - it still outputs heat below that, but not enough to keep
| my house warm and so I use the backup furnace a lot more than I
| want to.
|
| A previous house the heat pump was sized to work to 14F. They
| make them that will work down to -25F, but since it gets to -30f
| where I live (about once every 10 years, but that is enough) we
| need a backup system so is probably isn't worth getting a system
| sized to as cold as possible.
|
| Ground source heat pumps are a common option in rural areas -
| they cost a lot to install ($50k - and this is the cheapest
| version that needs a lot of land thus rural areas). They are
| likely to pay off if you live in the same house for 50 years, but
| the initial upfront costs are high (you do get a house worth $10k
| more than other heat option). Worth looking into if you are young
| and have reason to think you will live in the same house for 50
| years.
| quickthrowman wrote:
| It's very hard to say whether heat pumps are cheaper than NG for
| heating. I pay about $0.25 per 100k BTUs which is about 3kWh.
| 3kWh costs about 50 cents. As long as the COP is above 2, it's
| cheaper to _run_ the heat pump.
|
| Once you factor in an electrician and pipefitter for installing a
| heat pump, plus the cost of the heat pump, refrigerant, and
| furnace coil, I'd imagine you lose money in the long run.
|
| If you then additionally include the strain on the grid from all
| these new data centers without enough generation capacity, I'll
| stick with natural gas for heating air and water.
| SigmundA wrote:
| Its not hard to say at all, the math can be done pretty easily
| based on your local electric and gas rates, and most people who
| go for a heat pump already need an air conditioner for summer.
|
| The math actually works out in many places unless you have
| cheap gas and expensive electricity. Its also better then to
| burn the gas at a power plant at 60% efficiency then 300-400%
| efficiency at the heat pump than pipe and burn the NG at 80%
| efficiency in your furnace.
| SigmundA wrote:
| Recently went with heat pump water heater and cloths dryer, very
| significant energy savings and they both work great using around
| 1/3 the energy.
|
| Most of my energy is for HVAC cooling in the south and that is
| already a heat pump. The house is well insulated and also have
| solar so along with the water heater and dryer I am around net
| zero in mid summer and and now that temperature is more mild I am
| producing much more than using even with one EV as well.
|
| It really nice to have an all electric house along with at least
| one car and a large solar backup system I am pretty self
| contained and don't really have to change anything if grid goes
| down.
| TimTheTinker wrote:
| Nearly 2 years ago, we had a small tornado come through, taking
| out our electricity for a week. During that time, it was snowy
| and the outdoor temperature was well below freezing (it reached
| about -10degC (12degF) at night).
|
| Keeping my family warm was a real struggle that week. The next
| spring, I went to Costco and bought a big tri-power generator and
| wired up a generator interlock on the electric panel. Now if we
| lose power, we can run the natural gas furnace & blower with no
| problems. I can also power the generator from my home's natural
| gas supply instead of making frequent trips for gasoline.
|
| So I'd say _heck no_ to swapping the natural gas furnace for a
| heat pump. I 'd much rather use natural gas to power both the
| generator and the furnace/blower than risk needing more
| electricity to keep my family warm than my setup can handle.
| TimTheTinker wrote:
| All this push to electrify everything makes me nervous, as it
| effectively centralizes a lever that someone evil enough could
| use to coerce the general public in unsavory ways.
|
| I'm doubly suspicious of areas that combine mass-electrification
| with reducing availability of the most reliable alternate source
| of electricity (i.e. generators). California in particular is
| pushing to make generators increasingly hard to obtain.
| supportengineer wrote:
| >> someone evil enough
|
| There's so much evil being demonstrated today, in real time,
| that we can't dismiss this any more, it must be seriously
| considered.
| bethekidyouwant wrote:
| I moved from gas boiler to electric years ago and would like to
| move to an electric heat pump hybrid, but it doesn't exist.
| Moment lost.
| supportengineer wrote:
| I'm thankful to live in the Bay Area. One time we took a trip in
| the dead of winter. We turned off our heat completely. We were
| gone for a week. The coldest it got inside the house was 55
| degrees.
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