[HN Gopher] Attacking My Landlord's Boiler
___________________________________________________________________
Attacking My Landlord's Boiler
Author : ericvolp12
Score : 343 points
Date : 2025-04-22 04:27 UTC (18 hours ago)
(HTM) web link (blog.videah.net)
(TXT) w3m dump (blog.videah.net)
| willvarfar wrote:
| I guess your toolbox really shapes your solution space thinking;
| as I read through this, being completely lost in the whole world
| of RF whatnot, my mind jumped straight to an alternative attack
| that better fit my own tooling: could you encase the thermostat
| in a box that you can mechanically control the temperature of?
| kbuck wrote:
| Or attach an ESP32 to the boiler's control board that closes a
| dry contact circuit...?
| unsnap_biceps wrote:
| That was my first thought on how I would approach it as well.
| mschuster91 wrote:
| The problem is, if your landlord ever comes around for
| inspection, or the bloody thing breaks down due to your
| installation attempt, you can be held liable up to and
| including getting evicted.
| aceofspades19 wrote:
| Where can you get evicted for something like that? The
| worst case is that they would sue your insurance for
| damages, or you'd have to pay them out of pocket.
| avidiax wrote:
| This sounds good, except that cooling a box is problematic. He
| needs the temperature sensor to read low so that it turns on
| the heat.
|
| That said, if he has access to the interior of the thermostat,
| I'm sure it won't be difficult to replace the temperature
| sensor with a circuit to cause it to read either really high or
| really low on demand.
| toast0 wrote:
| > This sounds good, except that cooling a box is problematic.
| He needs the temperature sensor to read low so that it turns
| on the heat.
|
| Ice pack and desiccant?
| willvarfar wrote:
| I was literally imagining duck-taping one of those cheap
| electric "instant cooling" cups over the box on the wall, and
| running a small incandescent bulb in to be the heating up
| element.
| dtech wrote:
| For such a minor use case a peltier element is suitable. Very
| energy inefficient but you don't need much and it can both
| heat and cool.
| mjlee wrote:
| Or, assuming they have physical access to the combi boiler,
| removing the receiver unit and replacing it with a more Home
| Assistant friendly combi boiler thermostat.
|
| Probably a 30 minute job if you've never done it before and
| easily reversible with a little bit of double sided sticky
| tape, which all Brits should be familiar with if they ever made
| a Tracy Island. There is a real risk of electrocution which
| could be completely militated against by turning off the power
| to the boiler.
|
| Still, a fun hack, and nicely executed!
| haileys wrote:
| I removed the thermistor from inside my wall controller and
| wired in a digital pot instead. Achieves the same thing without
| physically heating and cooling the sensor
| nippoo wrote:
| Yes! You can indeed do exactly this. Look up CoolBot - they do
| exactly this, by just heating up the existing thermostat
| anal_reactor wrote:
| I've heard a story of people renting an apartment with locked
| thermostat to the legally allowed minimum. Tenants would put
| ice on the thermostat
| Gazoche wrote:
| I heard that was a well-known trick at my old uni dorm. There
| was a single thermostat for the whole floor so once people
| figured out where the sensor was, the ones who lived closest
| to it would often leave packs of frozen food on it.
| thomashabets2 wrote:
| If you do want to decode it, it's probably not that hard. I was
| going to implement the transmission side when I did this, but
| then I moved.
|
| https://blog.habets.se/2017/04/Decoding-FSK.html
| yurishimo wrote:
| If OP ever shows up here, you probably could have just replaced
| the thermostat with one that is compatible with your boiler for
| less money and headache. The boiler market is fairly open to
| competition as evidenced by the fact that you could find a
| Honeywell signal in a random OSS project that also worked.
|
| Good luck with your future apartment customizations!
| glitchcrab wrote:
| I think you missed where it was explained that the apartment is
| rented and therefore you cannot modify anything.
| Griffinsauce wrote:
| Cannot modify _irreversibly_ though right? Something like a
| Nest or whatever is easy to return to the original state when
| you leave.
| odiroot wrote:
| Replacing a thermostat is very easy to do though. And very
| easy to revert too.
|
| Usually it's just acting as a simple relay (on-off switch) so
| there's two physical wires.
|
| I've got my Hive thermostat running great with various Bosch
| and Vaillant boilers. And it works great with HA.
|
| Some newer boilers have 12V "smart" controls but still expose
| 230V "dumb" call for heating pins.
| mschuster91 wrote:
| > Usually it's just acting as a simple relay (on-off
| switch) so there's two physical wires.
|
| Vaillant has a proportional signal as well, and that thing
| in my old home was 30 years old... [1]
|
| [1]
| https://www.mikrocontroller.net/topic/126250?page=single
| glitchcrab wrote:
| Agreed (I set up our dual zone Nest-controllee heating so I
| know it's not difficult), but what happens if the landlord
| visits and isn't happy with you having done this? It would
| be a pain to have to revert this if you knew the landlord
| was coming.
| nkrisc wrote:
| Check your local laws. You may be allowed to do something
| like this by law.
| Tarq0n wrote:
| OP's thermostat wasn't wired, that's why he'd need the
| electrician.
| nkrisc wrote:
| Depends on jurisdiction, of course, but often you're allowed
| to modify things as long as you return it to how it was
| before when you leave. Obviously not quite as simple as that
| always but I would guess in many placing temporarily
| replacing a simple thermostat would fall under that.
| bethekidyouwant wrote:
| You just take the thermostat off the wall and put it in a
| drawer and then you buy a new thermostat and put it on the
| wall and then when you give the apartment back, you take the
| old thermostat and you put it back on the wall
|
| Also, if you read this far, are you German or something? you
| can just do things. which OP seems to know. And even if the
| landlord came and saw the apartment as long as the new
| thermostat isn't neon orange, he isn't going to notice and
| even if he somehow noticed you would just gaslight him and
| say no that's how it's always been and how the hell is he
| gonna escalate past that? And why would he if the new
| thermostat is more expensive and has better features?
| smelendez wrote:
| I wonder what the ideal one-size fits all thermostat looks like.
|
| The one in my apartment has a "feature" a lot of US thermostats
| now have, where you set four ordered times called wake, leave,
| return, and sleep and the temperature you want the space in each
| interval. I know very few people who actually live in a household
| where everyone wakes, leaves, returns, and sleeps on the same
| schedule every day.
|
| I work from home and personally just want to set a temperature
| and have the space stay at that temperature indefinitely but this
| system requires that I tap through and enter the desired
| temperature four times, while confirming the four intervals.
|
| I guess I'd be happier with a _more_ programmable thermostat that
| I could set to behave like an old school dial thermostat.
| Freak_NL wrote:
| Isn't this pretty much what these thermostats already allow? I
| have a new Honeywell Thermostat which basically does what the
| twenty years old one it replaced does with a few added
| conveniences in terms of UI. It has those
| wake/leave/return/sleep instants for each weekday (but also
| adds an optional second leave/return pair), and it has an
| option to override the day programme to 'holiday', which is
| essentially an eighth programmable weekday you can activate at
| any time.
|
| Your use case is possible with that. Just set the standard
| program to 15degC, and activate the holiday set to whatever you
| need whenever you want. Configure it to go to 15degC at some
| sensible time in the evening, so it won't go on even if you
| forget it.
| meindnoch wrote:
| 15 C is very cold. Are you American?
| Freak_NL wrote:
| 15degC would be the standard setting of 'no heating' (just
| keep the house warm enough to avoid mould and such). The
| 'holiday' programme would be 21degC or whatever is desired.
| That would effectively turn the thermostat into one where
| turn on the heating by putting it in 'holiday' mode, and
| can turn it off by exiting that mode or just letting it
| revert to 15degC after 23:00 or so.
| xattt wrote:
| My wife and I worked a six-week shift work schedule for a long
| time. We got second-gen nest thermostats when they first came
| out (2012) thinking they were neat.
|
| Nope! The smart learning feature was the biggest pain in the
| ass. You'd be sleeping during the day for a night shift, only
| to find yourself freezing because it decided no one was home.
| uptown wrote:
| You can turn off the feature that changes temp based on
| presence. Or disable dynamic scheduling altogether.
| xattt wrote:
| I ended up having to manually changing the schedule week-
| to-week.
| JoshTriplett wrote:
| I like the Nest, but I absolutely turned off all the "smart"
| features and just set a fixed temperature range and change it
| when desired.
| Cthulhu_ wrote:
| I'm still of the opinion that a dial works best. Especially in
| modern homes (in Europe at least), there seems to be a school
| of thought that you should just leave your thermostat at the
| same temperature at all times - the theory being that warming
| up a cold house in the morning costs more energy than
| maintaining a stable temperature.
|
| Anyway, my ideal setup would be to install 'smart' thermostat
| taps on every radiator in the house, either manually turn them
| down when you're not in the room or have them automatically
| detect activity or open windows and adjust accordingly. But
| each one has the authority to trigger the central boiler if
| needs be, instead of only the master thermostat in the living
| room.
| vladms wrote:
| I think in real life there are more constraints. For example
| there are people that sleep better at a lower temperature
| than the daily one (so leaving the thermostat at the same
| temperature it's a minus for them).
|
| Regarding "what is better" from energy efficiency, I would
| prefer a system that "check it" because my guess is that it
| depends a lot based on the individual situation. I mean
| everybody is going crazy over "IA" but a couple of sensors
| and a system smart enough to adjust your usage based on your
| particular situation and preferences (like "eco", etc.) is an
| exception.
| alistairSH wrote:
| In slightly cooler climates, the answer for sleep is to
| open windows. This works in much of Europe, even through
| summer.
|
| But of course, not really feasible in Atlanta or Phoenix.
| Nighttime temps are too warm.
| deno wrote:
| Open windows in a city often means you are invinting in
| pollution, both air and noise.
| JoshTriplett wrote:
| Exactly. Current HVAC systems have extensive filtration;
| some HVAC systems have HEPA filters.
| eru wrote:
| We are talking about places that need heating here.
|
| In general, you should either run the heater or have your
| window open. Both at the same time is bad news for your
| energy bill.
| miunau wrote:
| We've used the Tado system with a central boiler and smart
| radiator knobs for a few years. It's worked fine and hooks up
| to Home Assistant and can do the things you describe. I'm
| sure there are some alternatives.
| wickedsight wrote:
| > the theory being that warming up a cold house in the
| morning costs more energy than maintaining a stable
| temperature
|
| I've heard this theory a lot too, but it doesn't match with
| physics. A warm house loses more energy than a cold house,
| due to a higher temperature difference allowing easier heat
| transfer. So in most homes, with radiators and high
| temperature CV, it's way more efficient to just turn it off
| when you gone.
|
| One exception is when you have a very well insulated house,
| combined with floor heating and a very efficient, low
| temperature heat pump. In this case, it takes a lot of time
| for temperature to move in the house and it's already
| incredibly efficient.
| sz4kerto wrote:
| It does match physics if you consider other factors. Apart
| from the heat pump scenario, this statement can also be
| true when you have condensing boilers (and okay-ish
| insulation)
|
| The reasoning: when you heat up the house, then your boiler
| needs to produce constant high-temperature water. When you
| keep the house at the same temperature, then the boiler
| produces much lower temp water and it is more efficient.
|
| Insulation also matters because if your house has outer
| insulation then it means that heat transfer from the house
| to the environment is mostly blocked, but cross-room heat
| transfer is likely not (through the walls). Therefore it is
| better to heat the whole house than heating just a couple
| of rooms because if you do the latter then you'll end up
| heating the whole house anyway but you're using less
| surface area (meaning you need higher flow temperatures,
| meaning less efficiency).
| eru wrote:
| > The reasoning: when you heat up the house, then your
| boiler needs to produce constant high-temperature water.
| When you keep the house at the same temperature, then the
| boiler produces much lower temp water and it is more
| efficient.
|
| How does your boiler produce heat for your water in your
| scenario?
|
| > Therefore it is better to heat the whole house than
| heating just a couple of rooms because if you do the
| latter then you'll end up heating the whole house anyway
| but you're using less surface area (meaning you need
| higher flow temperatures, meaning less efficiency).
|
| Just model the other rooms as very weird wall to the
| outside.
| tgsovlerkhgsel wrote:
| > the theory being that warming up a cold house in the
| morning costs more energy than maintaining a stable
| temperature
|
| This is only true if the heating happens quickly _and_ the
| system is less efficient when heating quickly. Otherwise,
| this doesn 't make sense from a physics standpoint. A
| temporarily lower temperature differential means less kWh of
| heat lost.
| DamonHD wrote:
| This is a whole research topic, my PhD in fact!
|
| FWIW I run my heat pump intermittently and with locally-
| smart TRVs that get to call for heat centrally, and a
| weather compensation only flow temperature curve, and it
| WORKSFORME!
|
| https://www.earth.org.uk/heat-pump-16WW-control.html
| anotherhue wrote:
| I enjoyed reading this, thank you.
| DamonHD wrote:
| \o/
| rightbyte wrote:
| "Quickly" implies higher power which will make the air
| around radiators warmer than a slow heating.
|
| The losses are proportional to the temperature differential
| between outside and inside.
|
| So you should have somewhat higher losses from the hotter
| air streams from the radiators passing the windows.
|
| Dunno about magnitude though.
| adrianN wrote:
| Heating systems generally are more efficient when they need
| to output less power. Whether that cancels the increased
| heat loss seems to be a question that can't be answered in
| general.
| jmilloy wrote:
| I think that maintaining a stable temperature means warm
| walls/floors/furniture and potentially cooler air
| temperature, as opposed to a cold house with intermittently
| warm air. Most people can feel comfortable at a lower
| thermostat (air) temperature if the walls etc are warm due
| to maintaining a stable temperature. I don't have
| calculations or references, YMMV.
| Suppafly wrote:
| >Otherwise, this doesn't make sense from a physics
| standpoint. A temporarily lower temperature differential
| means less kWh of heat lost.
|
| This topic comes up anytime thermostats and heating are
| mentioned. The physics arguments only makes sense if you
| don't care about comfort. Most people would rather optimize
| for comfort with some energy/cost savings if possible and
| the physics folks seem to not care about comfort at all.
| KineticLensman wrote:
| (UK) my boiler has a control with something like the
| wake..leave timer (it actually has six settings for a midday
| period as well) and there is a separate thermostat with a
| temperature dial. The boiler also has a button that advances
| it to the next time interval if you want instant on (eg if
| you come home early to a cold house). I find this combo of
| controls meets all of my needs, given that I have a fairly
| repeatable daily schedule.
| eloisant wrote:
| > the theory being that warming up a cold house in the
| morning costs more energy than maintaining a stable
| temperature.
|
| That's true if you completely stop heating. However if you
| lower the temperature by roughly 3.5C when you're not home,
| you'll be saving energy.
|
| So you can for example program it to be 16C when you're out
| and 19C when you're in. You don't completely turn off heating
| indeed.
| tgsovlerkhgsel wrote:
| The obvious solution is a "wake time" of 8 am, "leave time" of
| 8:01, "return" 8:02, "sleep" 8:03. Then just set the sleep
| temperature to your desired temp and the remaining ones to
| something reasonably close, or if it doesn't automatically
| switch between heating and air conditioning, set it for the no-
| op for the season (i.e. the highest possible temp in summer,
| and the lowest possible in winter) for those three minutes.
| bob1029 wrote:
| > I wonder what the ideal one-size fits all thermostat looks
| like
|
| https://www.honeywellhome.com/us/en/products/air/thermostats...
| ThePowerOfFuet wrote:
| > I wonder what the ideal one-size fits all thermostat looks
| like.
|
| As you go on to describe, there probably isn't one.
| 542354234235 wrote:
| I have an Ecobee and I like it. It comes standard with Home,
| Away, and Sleep but you can put in as many or as few as you
| want. You can manually change the temp and you can also set how
| long you want your manual temp to "stick". Either until you
| cancel it, or until the next preprogrammed change. I like it
| cooler at night, so I have it change temp around my normal
| bedtime, which includes if I adjusted the daytime temp because
| I don't want to have to remember to change it back myself,
| that's why I have a smart thermostat. It detects when I leave
| the house and sets it to away, because I don't need it running
| as if I am at home. If I go on vacation I can set it to keep
| the house safe, but not comfortable, and change back around the
| time my flight lands.
|
| Unless you have a crazy random schedule, or you want the temp
| the same whether you are asleep, awake, or not at home, or i
| guess if you have different temp preferences every day.
| Otherwise you can program in a basic schedule and just adjust
| manually as needed. Nothing stops you from changing the temp
| manually if you wake up an hour early, but if you wake up on
| time, then you don't even have to think about it.
| quickthrowman wrote:
| > ideal one-size fits all thermostat
|
| The round Honeywell electromechanical thermostat with a
| bimetallic strip, invented in 1953:
| https://www.honeywellstore.com/store/products/honeywell-roun...
|
| 24VAC, dead simple, and reliable. My family's lake house has
| 50+ year old Honeywell round thermostats still in service.
| Suppafly wrote:
| >I guess I'd be happier with a more programmable thermostat
| that I could set to behave like an old school dial thermostat.
|
| I honestly prefer the older type. Ours is programable, but we
| just don't program it and always just set it to the temp we
| want. If we are feeling a little chilly on a cold day, we'll
| bump it up a degree, or down a degree when it's particularly
| sunny and everyone is feeling warm.
| YakBizzarro wrote:
| Funny how the manufacturer proudly claims that the protocol is
| encrypted, but completely forget to mitigate replay attacks,thus
| making the encryption completely useless
| kleiba wrote:
| Which raises the question whether the OP now unknowingly also
| controls the heater in the apartment next to his...
| mattigames wrote:
| And so the heat-stroke-killer was born, offing his victims
| with rapid changes between coldest and hottest setting,
| natural death has never been this human-made.
| simooooo wrote:
| Probably not otherwise the original would also potentially
| run that risk
| kleiba wrote:
| Good point!
| mhw wrote:
| Unlikely. This kind of wireless thermostat has two parts: the
| thermostat itself, and a separate receiver box that's
| directly connected to the boiler. There's usually a pairing
| process that you can go through where the two parts negotiate
| a shared value used in the protocol; this prevents one
| thermostat unintentionally controlling other boilers. You can
| see this described in the Installation Guide for the
| thermostat linked from the article (it's called 'binding' in
| the guide).
| videah wrote:
| The thermostats are paired, if my setup was able to control
| another apartments boiler then the original thermostat would
| also do that
| globular-toast wrote:
| Ah yes, the classic problem of people using crypto primitives
| without fully understanding the problems they're trying to
| solve. Anyone even remotely interested should look into a full
| protocol like TLS or PGP to see how many primitives like block
| ciphers, hashes, etc. are involved and why.
| badmonster wrote:
| loved the blend of reverse engineering and persistence
| __turbobrew__ wrote:
| The legit Hackrf One is known to have frequency smearing, I
| wouldn't use one off Aliexpress to transmit without testing it
| with a spectrum analyzer first (which you probably don't have if
| you are buying knockoffs from Aliexpress).
| KeplerBoy wrote:
| What does frequency smearing mean in this context?
| tgsovlerkhgsel wrote:
| You're trying to transmit (only) on e.g. 433 MHz, but you
| actually transmit on 433 MHz and a bell curve around it.
| KeplerBoy wrote:
| so, severe LO clock drift?
| __turbobrew__ wrote:
| Not exactly, the transmitted power tends to be centered
| on the frequency you desire, but there are unwanted
| harmonics off the center frequency. Its like having a
| fire hose that hits the desired target with water
| (something on fire), but it also hits everything else
| around the target in a large radius as well which may be
| very sensitive to water (precious art, high power
| transformers, etc)
| tgsovlerkhgsel wrote:
| The blogpost mentions "I guess it's always good to have another
| SDR just to confirm that we're not polluting other
| frequencies." and they have an RTLSDR which probably could
| serve as a good enough spectrum analyzer for this use case?
| solarist wrote:
| One doesn't actually need any extra hardware for this... just 8cm
| of wire and this https://github.com/F5OEO/rpitx
|
| (use at your own risk of course)
| LeonM wrote:
| From the linked repo:
|
| > rpitx is a general radio frequency transmitter for Raspberry
| Pi which doesn't require any other hardware unless filter to
| avoid intererence. It can handle frequencies from 5 KHz up to
| 1500 MHz.
|
| Wait, how does that work?
|
| 1.5GHz is a _lot_, I can't imagine this is done with bit-
| banging an I/O line, nor do I expect the Pi will have a DAC
| with anything close to a 3GHz+ sample rate.
|
| > Plug a wire on GPIO 4, means Pin 7 of the GPIO header (header
| P1). This acts as the antenna.
|
| A bit of Googling shows me that on the later Pi board GPIO4
| (pin 7) has a bunch of alternative modes, amongst which is a
| general purpose clock output (GPCLK0), a DPI output bit
| (DPI_D0) and what I recon is composite analog video in/out
| (AVEOUT_VID0, AVEIN_VID0), and the TDI JTAG pin. But none of
| these would get close to 1.5Ghz TRX capabilities, no?
|
| What's the magic here?
| solarist wrote:
| RF is basically black magic but here it's the harmonics of
| lower frequencies that are in GHz range (and very noisy and
| weak)
| videah wrote:
| This did come up when I was researching this but it's
| incredibly dangerous as you'll be spewing all over the spectrum
| due to harmonics, I considered it too much of a hack for my
| liking
| Mond_ wrote:
| Cool as fuc + very nice blog design.
| pyfon wrote:
| Furry cartoons are catching on.
| buccal wrote:
| Cool project.
|
| Speaking of newish natural gas (CH4) heaters, they all should
| have modulating thermostat capability with OpenTherm/eBus or
| other protocol. Combined with a thermostat with outdoor
| temperature sensor system efficiency is increased a few percent
| and that should help offset thermostat and installation costs. In
| the end you have more efficient modern heating system.
|
| Same should apply for heat pump systems.
| steelegbr wrote:
| OpenTherm is a cool idea but even new installations aren't
| always wired for it. When installing a new smart thermostat I
| found the installation has been wired as S Plan with the few
| cables running between the boiler location and valves location
| already consumed. Makes the job much bigger if you're not
| prepared for it.
| buccal wrote:
| There are many wireless OpenTherm thermostats. Wired is
| better but is not required for modern thermostats.
| alistairSH wrote:
| Is this a non-standard thermostat control mechanism? I don't know
| what's common in apartments. All my houses have the thermostat
| wired to the HVAC (and are easily replaceable by the resident).
| sokoloff wrote:
| > I also have it so the heating turns off when I go into town and
| turns back on when I'm just a few train stops away so my place is
| nice and toasty for me getting home!
|
| If your goal is saving energy/money, you _don't want_ a system
| capable of going from cool to toasty in 20 minutes.
|
| Instead, you want a system that runs (much) lower water
| circulation temperatures (giving lower losses in the
| unconditioned spaces and more even room heating). That can be
| done to any condensing boiler by just turning down the flow
| target temperature.
|
| A second layer of optimization on top of this is the addition of
| outdoor reset/weather compensation which will adjust that flow
| temperature based on the outside temperature, giving a flow
| temperature than can _just barely_ restore the building to the
| desired setpoint temp.
|
| With mine properly tuned, I was targeting having the thermostat
| act more like a high-limit and for it to call for heat between 22
| and 24 hours per day while not overheating the house. That often
| meant flow temps in the 110degF (warm day) to 135degF (below
| freezing day) range. Compared to the prior winter (at a constant
| 160degF flow), the house used 8-15% less gas and was wildly more
| comfortable. (This setup does preclude using deep setback
| settings, which also can save money, because recovery times are
| necessarily long in such a scheme, unless you have an even
| smarter control system that can run perfectly tuned water most
| times but hotter water during recovery from setbacks.)
| frereubu wrote:
| I've read that it's always more efficient to turn heating off
| when you're not home and then turn it back on when you return.
| Is the reason for it being on 22-24 hours here that it takes a
| very long time to get back to the desired temperature, meaning
| you'd actually be cold for quite a while as it returned to the
| desired temperature?
| sokoloff wrote:
| I work entirely remote so, other than travel, there are not
| many long periods when the house is unoccupied.
|
| I target the long run time to maximize efficiency. A 160degF
| pipe will lose more heat to the part of the building that I
| don't want to heat as well as more heat to the wall right
| behind the radiators. It also results in the house going
| micro too-hot, too-cold, too-hot, too-cold as it cycles. Mine
| is constantly trickling in just enough heat to replace the
| heat lost instead of cycling between adding way more than
| needed then none for a while.
|
| Another large effect is that low return water temperatures
| into the boiler allow for greater condensation of exhaust gas
| energy to be used in the building instead of sent outside.
| Walking by my house on a cold day, you'll see minimal steam
| plume during operation. All that steam I see my neighbors
| emitting is energy they paid for and delivered to the
| outside... (They paid a lot for a boiler with a 95% or 98%
| sticker and run it at 80% efficiency.)
|
| https://kw-engineering.com/how-to-optimize-condensing-
| boiler...
| Retric wrote:
| > A 160degF pipe will lose more heat to the part of the
| building that I don't want to heat as well as more heat to
| the wall right behind the radiators.
|
| You've got the first part of that backwards, it's the walls
| near your radiators that are your problem and need more
| insulation.
| sokoloff wrote:
| Indeed the building is 100 years old and impractical to
| retrofit insulation in any cost-efficient way (structural
| brick, lathe and plaster walls with about 1" of air space
| in the original parts of the building).
| frereubu wrote:
| Thanks for the explanation.
| eru wrote:
| Btw, a heated blanket would be a lot more efficient, as it
| warms just your butt.
| sevensor wrote:
| Heated blankets are ok, but you have to arrange them just
| so, and then you can't move without fussing with the
| cord. It's the last resort after layering warm clothes
| before bumping up the thermostat.
| pests wrote:
| I use a heated blanket as a bottom layer sometimes. Lets
| you move around and do whatever you want with the blanket
| fixed in place and the cord not in the way. I have larger
| heated blanket that has independent power/settings for
| each half. I turn one half on max and leave the other off
| and can roll and find the perfect direct heat and if
| using another regular blanket on top all that is captured
| too.
| amluto wrote:
| > Another large effect is that low return water
| temperatures into the boiler allow for greater condensation
| of exhaust gas energy to be used in the building instead of
| sent outside.
|
| Correct.
|
| > Walking by my house on a cold day, you'll see minimal
| steam plume during operation. All that steam I see my
| neighbors emitting is energy they paid for and delivered to
| the outside... (They paid a lot for a boiler with a 95% or
| 98% sticker and run it at 80% efficiency.)
|
| Please check your assumptions.
|
| A boiler operating in condensing mode will produce a
| trickle of liquid condensate (that may well be drained
| somewhere that you can't see [0]), teeny tiny drops of
| condensate suspended in gas (colloquially "steam", but it's
| more like fog), and some residual water vapor mixed with
| the exhaust gasses. You can see the "steam", but you cannot
| see that residual vapor except to the extent that it
| condenses further as the exhaust stream cools after it
| exits, much as you can see some of your own exhaled water
| vapor on a cold day as it condenses outside your nose or
| mouth. The exhaust gas is saturated: it has maximum
| humidity and is at its own dewpoint, so there is a lot of
| visible fog. The droplets that form inside the boiler and
| escape with the flue gas do not represent wasted heat:
| their heat of fusion has been captured.
|
| A boiler operating in non-condensing mode will produce no
| liquid condensate, and its exhaust will be well above its
| own dewpoint. It will contain far more water vapor than a
| condensing boiler, but _you cannot see that vapor_ except
| insofar as the flue gas has a different index of refraction
| than the surrounding air and distorts the background a bit.
| Depending on weather, a bit of it may condense later. All
| of it is wasted energy.
|
| [0] This liquid condensate is nasty stuff: it's basically
| carbonated distilled water plus some impurities but not
| usefully buffered, and it's rather acidic. It will quickly
| corrode many metals, including copper and many common
| copper alloys, non-stainless steel, galvanized steel, etc.
| Non-condensing furnaces and boilers are generally carefully
| engineered to avoid condensation, because the condensation
| would damage them. If your plumber is unaware of the degree
| to which boiler condensate is corrosive and uses copper
| pipes or metallic fittings (push-to-fit in the style
| commonly sold as "Sharkbite"), the system will fail. Use
| plastic pipes (PVC or PEX) and _plastic_ (or maybe
| stainless steel) fittings such as ordinary solvent-cement
| PVC fittings, "engineered plastic" PEX fittings, or push-
| to-connect fittings with _plastic_ wetted surfaces. John
| Guest makes these, and there is also the somewhat bizarre
| ProLock brand, which seems to be some sort of joint
| offering from John Guest and Sharkbite.
| sokoloff wrote:
| I'm imagining that what I see in my neighbor's exhaust is
| the subsequent condensation as their exhaust gas cools to
| where the dew point is met and visible moisture becomes
| apparent.
|
| I can see a clear difference between running my own
| boiler at 25degF OAT (lots of "steam") versus 40degF OAT
| (almost none) while I see my cross-street neighbor
| showing large plumes on both. I'm not sure if I mistyped
| above or I'm actually thinking about it wrong, but I
| don't think my observations are incorrect.
|
| Having that water condense outside the building (giving
| up heat to the neighborhood) is less efficient than
| having that water give up its heat into the incoming
| (return) water.
| leoedin wrote:
| The hidden factor here is that condensing boilers and heat
| pumps have non-linear efficiency vs flow temperature curves.
| Heat pumps in particular show high increase in coefficient of
| performance (CoP) as flow temperature drops.
|
| The other variable is how well controlled your heating is. A
| lower flow temperature means less overshoot of the target set
| point - and as losses scale linearly with temperature delta,
| that can mean higher energy losses (depending on the
| characteristics of the controller of course).
|
| Whether or not you care about losses in unheated spaces
| depends on your system topology. Personally, all my heating
| pipes are within the thermal envelope of my house, so flow
| temperature has no bearing on those losses at all.
|
| If you had a resistive electric boiler, flow temperature
| would have absolutely no effect on efficiency. You'd be
| completely right, that running heating only when you needed
| it would be more energy efficient.
| frereubu wrote:
| Thanks for the explanation.
| looofooo0 wrote:
| You missing ISO7730, it is a system for humans and not air
| temperature control. (tl;dr heating your home 24/7 allows
| you to lower air temperature for the same comfort. )
| rsynnott wrote:
| > I've read that it's always more efficient to turn heating
| off when you're not home and then turn it back on when you
| return.
|
| 50 years ago this was _always_ the case, but condensing
| boilers and especially heat pumps muddy the waters a little.
| Condensing boilers can be close to 100% efficient (vs ~70-80%
| for ye olde gas boilers), but generally only at a fairly
| specific operating temperature, which may be lower than you'd
| need to get a rapid rise in temperature. Heatpumps are >100%
| efficient (that is for every joule of electricity you put in
| they move more than one joule), but are even more fussy about
| operating temperature.
|
| The answer now is going to be a solid 'it depends', based on
| behaviour of the heating system, outside temp, desired inside
| temp, insulation...
| looofooo0 wrote:
| ISO 7730 to the help. Just keep low overall temperatures
| and heat 24/7 in a reasonably insulated home.
| Retric wrote:
| That's an artifact of how heating is setup inside your home.
| Which is more efficient depends on where you're dumping heat
| inside the home, levels of insulation, etc.
|
| Energy moves from hot to cold linearly with temperature
| differences. Hypothetically, if the pipe was the same
| temperatures as the inside of your home all the heat
| transferred would be outside the envelope. The hotter the pipe
| the better this ratio becomes. This is true regardless of what
| percentage of the pipe is inside the envelope.
|
| However, heating along the exterior of the home under windows
| and such then you'll heat the exterior walls to higher
| temperatures than the interior thermostat thus losing more heat
| to the outside. Radiant heating on the other hand largely
| avoids this effect.
| DamonHD wrote:
| I moved all my radiators away from under windows (and
| upgraded the windows to triple glazing) to avoid maximising
| the temperature differential and energy loss through the wall
| under the windows, while eliminating the cool drafts that the
| under-window radiator placement was intended to counter.
| HPsquared wrote:
| What do you do for ventilation?
| DamonHD wrote:
| The windows all still open, but in winter we have
| (nearly) enough MHRV (Mechanical Heat Recovery
| Ventilation) not to need to ventilate directly, eg see:
|
| https://www.earth.org.uk/MHRV-mechanical-heat-recovery-
| venti...
| sudahtigabulan wrote:
| Do you mean you moved them to another wall, or just
| increased the gap?
|
| (not a native speaker here)
| DamonHD wrote:
| Moved them to another wall.
|
| Eg: https://www.earth.org.uk/note-on-superinsulating-
| bedroom.htm...
| Benanov wrote:
| Radiators were originally designed to heat more than
| needed, so you could open the windows.
|
| In New York, at least - the standards were never changed to
| accomodate for closed windows in 1920. Snopes has a
| rundown. https://www.snopes.com/fact-check/apartment-
| radiator-pandemi...
| organsnyder wrote:
| My house (built in 1916) was insanely over-provisioned.
| When we upgraded to a modulating-condensing boiler, we
| halved the BTUs and are still able to easily keep the
| house heated to any desired temperature even on the
| coldest winter days.
| DamonHD wrote:
| I'm really confused about (not complaining, just not
| understanding) the downvotes.
|
| These are statements of neutral fact, and the whole process
| is described in some detail on my site, for each room that
| we retrofitted.
|
| I don't understand if I have caused offense or something:
| apologies if somehow so!
| joncrocks wrote:
| I'm not sure, but I think that the reason that radiators
| are placed near windows (at least historically) was to
| avoid hot/cold spots in rooms.
|
| By placing the radiator near the place that is likely the
| coldest place in the room, you ensure that the room is an
| even in temperature as possible. Rather than to
| counteract 'cool draughts'. I think.
|
| So perhaps people thought that your initial comment was
| wrong/misleading.
|
| But if you have triple glazing and this mitigates the
| heat loss, then the coldest wall of your room may no
| longer be the one with a window, so you may well be doing
| the right thing for your room(s).
| DamonHD wrote:
| Even if the coldest wall is still the exterior one (it
| should be, thermodynamically), best maintaining comfort
| in the room need no longer be by pumping heat out through
| that wall (or window) to reduce thermal gradients in the
| rest of the room. Those residual gradients (and, eg, cold
| drafts down those cooler exterior walls) can be small
| enough to not need fixing any more.
| looofooo0 wrote:
| Look at ISO 7730, a lot of comfort comes from non-cold walls
| and their radiant heat and small difference of wall
| temperatures to air temperatures. So having a thoroughly
| heated home allows you to lower your air temperature. Apart
| from that modern gas and even more heat pumps greatly gain
| efficiency by lowering flow water temperatures.
| Retric wrote:
| It's a deep rabbit hole as condensation, humidity, etc also
| enter the picture. Efficiently lowering temperatures for
| sleeping further complicates things.
|
| That said, heat loss is through exterior surfaces so you
| really want to avoid spot heating of poorly insulated
| exterior walls. Thus the design of baseboard heaters can
| make a larger impact than you'd think.
| looofooo0 wrote:
| Baseboard heaters need very high temperatures. I would
| not recommend installing this anywhere. Having big Typ 33
| heaters for temperatures below 45degC will greatly
| increase efficiency of your heating system. Otherwise, a
| split air con is also an efficient way of heating.
| sokoloff wrote:
| Baseboard heaters are often sized such that very high
| temps are needed (because that's what cheapest/lowest
| labor/least space used), but they don't have to be sized
| that way. In the attic bedroom, we have baseboards around
| the entire perimeter on two walls and same in the bath. I
| run the attic zone on the same water temp (outdoor reset
| controlled to be quite low) as the rest of the house
| (mostly large cast iron rads, one cast iron convector).
| Good insulation and air sealing in the attic means that
| the attic zone calls way less than the downstairs.
| looofooo0 wrote:
| Which is not exactly efficient. 40C or less is desirable.
| sokoloff wrote:
| My return water temps are 115F (46C) on a P98 design
| heating day, and obviously cooler on warmer than design
| days. Cooler is always better, but "baseboards require
| 180F [82C] water because that's what's on the spec sheet"
| is a commonly-held but mistaken belief.
| looofooo0 wrote:
| This is bad. Return water should be less 35 degree max.
| Actually 30 degree after the heat pump would be ideal:
| https://www.flow30.de/
| jillyboel wrote:
| [citation needed]
| looofooo0 wrote:
| Ah this is school knowledge of thermodynamics: the
| smaller the delta the more efficient the heat pump. For
| human comfort look at the iso7730. Also the system is
| self regulatory with such low temps.
| aesh2Xa1 wrote:
| Having read that document, the ISO 7730 model itself
| depends on stable temperatures. However, I think the key is
| simply to understand thermal mass; people can be in hotter
| air, but feel cold due to cold surfaces (e.g., floors or
| furniture), which heat more slowly (or lose heat more
| slowly) than the air itself.
|
| Therefore, 1st: Heating/cooling cycles from your HVAC are
| fighting these objects because they don't mix at the same
| speed as other objects (e.g., the air itself), so you end
| up with gradients across objects; people rate this feels
| unpleasant.
|
| 2nd: Mechanical equipment tends to operate more efficiently
| under constant load compared to constant start and stop
| cycles.
|
| With #1 and #2, you can just heat constantly to increase
| both the uniformity of heating across objects and also the
| efficiency of the mechanical equipment's energy conversion.
|
| There's a 3rd point, which, really, is just a sneaky way of
| reframing #1 and #2, and that is that you can also lower
| your setpoint and still have a subjectively superior
| comfort perception compared to a cyclic system. It drives
| home the point to say "constant 68F feels more comfortable
| than intermittent 72F." But it also invites the complaint
| about constant versus intermittent energy use, right? So I
| think just detailing #1 and #2 is better.
| looofooo0 wrote:
| https://www.krantz.de/wp-content/uploads/2024/04/layout-
| spec...
| aesh2Xa1 wrote:
| That spec aligns with my understanding, including the
| model's dependence on comfort perception. I was,
| initially, in disbelief about it, but changed my mind
| after reading thru. The texty reply was to make it more
| palatable for someone like me to accept. I think we
| agree.
|
| One thing I missed in summary is the concept of general
| radiant temperature gradient. It's not only about the
| gradient for conduction, but for radiation (and
| convection). So you could probably improve my summary by
| talking about any gradient between different objects in
| the environment and their EM, which feels unpleasant (but
| I think it had value in its reduction of the problem,
| too).
| sz4kerto wrote:
| > If your goal is saving energy/money, you don't want a system
| capable of going from cool to toasty in 20 minutes.
|
| Depends. As explained in a sibling comments, I have some rooms
| that have combined UFH and radiators, and if the desired temp
| is more than 1 celsius away from the current temp, then both
| are driven, otherwise it's just the UFH.
| sokoloff wrote:
| Indeed "depends" is almost always the answer.
|
| So long as you can get the boiler return water temps low
| enough, you can operate the boiler in its high efficiency
| range.
|
| Most dual-temp setups are set for the highest temp and mixed-
| down to provide the lower temp for under-floor. That's
| cheapest in terms of equipment and install but cannot be as
| efficient as a system that mixes down when both loads call
| but also lowers flow temp (thereby lowering return temp) when
| no high-temp rads are calling.
| quickthrowman wrote:
| This is a great post which describes how most commercial
| boilers are controlled. I'm looking at a sequence of operations
| for a boiler project I did recently and the hot water supply
| setpoint for -20F outdoor air is 145F and for +45F the hot
| water supply setpoint is 120F.
|
| Most home boilers lack an outdoor air reference temp sensor but
| all commercial boilers have them.
|
| Also, condensing boilers are amazing, the size difference alone
| vs an old tube boiler is wild, very small in comparison.
| looofooo0 wrote:
| Agree, switching on and off is the worst way of heating. If you
| look into ISO 7730, then a lot of comfort comes from non cold
| walls: https://de.wikipedia.org/wiki/ISO_7730 This means that
| in a reasonable insulated home, your best bet for comfort is to
| just keep the temperature constant and low like 20degC. This
| also allows you to lower your water temperatures which improves
| efficiency of your heat pump or boiler.
| static_motion wrote:
| Depending on the region, "reasonably insulated home" really
| is the factor that makes this not so viable for a lot of
| people. In my Mediterranean-adjacent climate country, most
| homes are just not well insulated at all, and having heat
| running 24/7 during winter is extremely costly and
| inefficient even if the heating is on a low setting.
| looofooo0 wrote:
| These home will most likely have a split air con, which
| will be the most efficient way of heating them. Also there
| is so much other room for improvement like drafty windows
| and doors etc.
| walrus01 wrote:
| In many warmer climates, the mini split air conditioners
| sold are cooling capability only. This is much cheaper to
| purchase for a 12,000 up to 24,000 btu/h unit than one
| which is also capable of heating the interior.
| looofooo0 wrote:
| Not true, I can buy a Chinese 4kw Model for 650EUR which
| can heat till -15degree. Doubt that you can save much.
| walrus01 wrote:
| Go price air conditioners in the uae or Kuwait or
| similar, the cooling only models are very much a thing
| that exists on the market.
| Syzygies wrote:
| Yes!
|
| I used to divide my time between a concrete hulk of a NYC
| apartment building, and a California home insulated to
| notoriously poor California standards. I was plenty warm in
| New York winters just from my neighbors' heat nearly all of
| the time. In California, there was a narrow window (think
| "Apollo 13 re-entry") between too cold and too warm.
|
| Then we modernized ceiling fans, and I hit on running them in
| "winter mode" drawing hot air up to flow back down the walls.
| Bingo! I love that ISO 7730 confirms this.
| dheera wrote:
| Capable doesn't mean it always puts out that amount of heat.
|
| A well-designed system would have good insulation, can dump
| 10000W watts of heat out and bring the room from cool to toasty
| in 5 minutes, and then scale back and maintain the temperature
| after that by putting out 500W after that.
|
| This also tends to be more efficient in practice because if you
| _know_ it only takes 5 minutes to heat up you are less likely
| to want to leave it on when you 're not around.
| organsnyder wrote:
| But it can't heat up the walls and other surfaces in that
| amount of time. The building will feel colder for the same
| air temperature setting until those objects have had time to
| warm up as well.
| DecoPerson wrote:
| The Flipper Zero is great, and could handle all of the
| hacking/investigation part by installing custom firmware.
|
| The original product understandably arrives with heavily-
| restricted firmware (I imagine to reduce the amount of flak the
| company receives). However, it is incredibly easy to install
| Flipper Unleashed or similar, which removes all said restrictions
| and adds a lot of additional functionality.
|
| Possessing the tools that could be used to commit a crime is not
| necessarily a crime in and of itself! Just be careful with what
| you do or, depending on what country you're in, you might find
| some men in suits knocking at your door.
|
| Personally, I wanted to replay "encrypted" 433MHz signals for my
| own devices (electric gate, roller door, roller shutters, ...)
| and this was disabled with the Flipper's region set to Australia.
| 0xEF wrote:
| > Possessing the tools that could be used to commit a crime is
| not necessarily a crime in and of itself!
|
| While I do agree 1000%, I also want people to be careful with
| this thinking since I have gotten in some minor trouble in the
| past. Always assume the authority questioning you can and will
| create whatever narrative they wish, that it will be accepted,
| and that your own reasoning will likely be used against you.
|
| I will always encourage exploration and curiosity in tech, but
| if we stick with the Flipper Zero example, there's a few things
| one should keep in mind, regardless of the jurisdiction they're
| in:
|
| * Don't carry it around unless you intend to use it.
|
| * Read all documentation before you start practicing, then
| practice being subtle.
|
| * Taking a note from my outdoorsy side, adopt the "leave no
| trace" ethos.
|
| * Pay attention to the effect your presence and actions have on
| the environment and your target and how that might be
| interpreted by an outside observer, then take action to
| mitigate suspicion.
|
| These apply to lots of devices, everything from your disposable
| smartphone to a cheap RFID card copier from Temu.
|
| Our eagerness sometimes gets the best of us, especially new-
| comers, and we want to jump to the part where we can be like
| the hackers we see in tv and video games. There's a reason
| those guys are fictional characters. Innocuous actions or not,
| the perception of the authority questioning you is all that
| will matter, in the end.
| crtasm wrote:
| Or perhaps go for the opposite of subtle - in many places
| it's quite normal to see people in hi-vis vests taking
| readings etc.
| butlike wrote:
| The 'shade curve' as I call it, where one reaches a point
| where their actions could be considered so shady, it's
| automatically assumed it couldn't possibly be them.
|
| Smoking pot in a dark parking lot with friends at night
| gives more cover, but smoking pot walking down your city's
| main street in the middle of the day gives you the cover of
| just smoking an innocuous "rollie," like any other person
| could be.
| JoshTriplett wrote:
| It's hard for anyone with a nose to mistake one for the
| other.
|
| (The underlying point is completely valid, though.
| Audacity is a powerful thing.)
| 0xEF wrote:
| That's an excellent additional thing to consider and I'm a
| bit mad that I neglected it since I have _accidentally been
| that guy._
|
| My job requires me to wear hi-vis (as well as other PPE)
| and it is crazy how little security pays attention to me in
| some of the very-big-name plants I visit, often with a
| laptop bag full of flash drives and a bunch of other tools
| that allow me to get into the machines.
|
| Early in this part of my career, I found myself in a very
| large plant for the first time, and my escort got pulled
| away on some other task (I now expect this to happen since
| it's such a common occurrence), leaving me to fix the
| machine I was working on. The place was the size of a small
| town, and I needed to use the restroom, but nobody was in
| the vicinity to ask, so I did my best to follow the floor
| markings and signs. Found it, but took a wrong turn coming
| back and found myself in a completely different area. Since
| I was new, I tried to find my way back without asking
| anyone I saw because I did not want to look stupid, but
| nobody stopped me, questioned me, etc.
|
| Probably one of the best lessons in social engineering is
| looking like you're supposed to be there.
| aeturnum wrote:
| One should not practice these things in actual high
| security areas, but it can be fun to simply walk around a
| strange place with a look of purpose and velocity. Not
| making eye contact, perhaps on a phone. As long as you
| won't get in trouble it's easy to practice the body
| language of belonging and that skill can be really useful
| even if you are not trying to use it for malicious
| purposes (i.e. if you are actually supposed to be there,
| the best thing for everyone is you look the part and
| don't cause more worry than required).
| johnwalkr wrote:
| I used to do contracted engineering and maintenance work
| in railyards, and in each facility would obtain (always
| with permission from my recollection) a well-worn
| supervisor vest and hard hat. They are usually color-
| coded.
| NoSalt wrote:
| > _" Always assume the authority questioning you can and will
| create whatever narrative they wish, that it will be
| accepted, and that your own reasoning will likely be used
| against you."_
|
| And with that, I give you:
|
| Don't Talk To the Police:
|
| https://www.youtube.com/watch?v=d-7o9xYp7eE
| sz4kerto wrote:
| We've moved to an new apartment (house) and we had to do a full
| renovation. It doesn't have modern insulation and I calculated
| that for the time being the ROI on insulation isn't worth it.
| It's a multi-floor semi-detached house and I wanted the best
| comfort and the most economical heating possible.
|
| In particular: stable and individually adjustable temperatures
| for bedrooms and living rooms; underfloor heating in some rooms
| (bedrooms), radiator-based heating in some others (living room),
| and combined UFH+radiators in some others (where UFH might not be
| enough during extreme colds).
|
| I thought I can just pay someone some money and they'll set up
| the controls for me. It must be a simple exercise, right?
|
| I could not have been more wrong. After spending a few hours of
| understanding the setups that "experts" have recommended, I
| figured out edge cases where they would be either wasteful or
| uncomfortable (meaning: unnecessary and inavoidable temperature
| overshoots or undershoots, etc.). I had many-many rounds with
| Honeywell, Tado, Siemens, etc. and every single one of them had
| _major_ issues.
|
| The renovation got a bit stuck because of this, but the plumbing
| was ready so I wanted to see whether the pluming and pumps are
| working, at least. So I connected the pumps and valves to "smart
| plugs", i.e. Zigbee-controlled plugs, so that I can see that they
| turn on. They did, which got me thinking...
|
| Right now I have $20 Zigbee temp sensors sprinkled across the
| house, $30 smart plugs and relays driving valves, pumps and the
| boiler, and Home Assistant is controlling the whole thing.
| Everything works perfectly and I could implement some features
| that simply no system would have done out of the box, for example
| in rooms where there's combined UFH and radiators I can drive
| both heating systems when the target temperature is far from the
| desired (so that the room heats up quickly) but as the room temp
| is getting closer to the target, the radiators are turned off so
| that UFH dominates heating (more comfortable and more energy
| efficient than radiators). In rooms with radiators, temp is +-
| 0.4 C within target, in rooms with UFH, it's +-0.1C within
| target.
| darkwater wrote:
| Yeah, the automated/remote controlled heating system world, and
| also the ringbell world is basically a giant scam, since they
| are updates on world that also scammed you in the past. I cried
| when I shelled out so much money for my Tado device, but even a
| dumb bTicino device costed in the hundred of euros realm, and
| it's just a sensor + a small LCD display and a designed-in-hell
| menu system to program it. And the same happens in Ip-based
| ringbells. A Doorbird will cost you hundreds of euros for what
| is basically a webcam plus some nice metal casing and a shitty
| software, but it competes with analog systems with optic cables
| etc that cost basically the same or more.
| rightbyte wrote:
| Sounds like a nightmare for a future buyer to operate.
|
| Some people are unlucky enough to buy homes where a machine
| engineer designed the boiler setup and the boiler room have
| enough valves and manometers to like operate the engine of
| Titanic.
|
| I guess programmers are the new sinners in this area nowadays.
| evrimoztamur wrote:
| The existing professional setup was also a nightmare, what
| gives?
| rightbyte wrote:
| Well first of I am envious and I would want to do something
| similar.
|
| If I inherit a heating system I want it to be all
| mechanical except maybe the control system for any heating
| pump.
| sz4kerto wrote:
| If we ever sell this (which we don't plan to), I know what to
| install (it'll be quite good, just not this perfect). I have
| it in a cupboard (a Siemens Connected Home thermostat
| system), the downside of that is that the combined
| UFH+radiator rooms will be less comfortable.
|
| (But still more comfortable than 99% of the houses I've been
| in.)
|
| I haven't mentioned in the parent comment but as a test I've
| dismantled the HA system and installed the Siemens system and
| it works well, just not 'perfectly'.
| rightbyte wrote:
| Sounds well thought out. Many seem to forget designing for
| replacing.
|
| In generall I think all these IoT systems will be a major
| headache as they age.
|
| My thermostats on the radiators are 45 year old by now.
| That is kinda the expected service life we are used to.
| sokoloff wrote:
| For every John Siegenthaler and Dan Holohan, there are
| thousands of mechanical engineers and tens of thousands of
| plumbers who are happier to slap in a $20K 4-hour boiler
| retrofit. There's not enough extra money in catering to the
| 0.1% of homeowners who care about the details.
| amne wrote:
| a bit off-topic: Are you running a single boiler and if so, how
| are you mixing UFH with radiators given there's a ~20 _C
| difference between the recommended temps for the two?
|
| My knowledge is that for UFH you run at temps between 40-50_C
| and radiators run at 60-70*C.
| sz4kerto wrote:
| UFH has mixing valves, so it runs on 38 C and radiators run
| on 55C. Single boiler.
| cameronh90 wrote:
| Off the shelf systems aren't only optimised solely for
| efficiency. They're made to be simple enough that an installer
| with half a day's training can do a few multiplications and
| additions to set the parameters that'll give you a tolerable
| percentage of optimal in the situations that equipment is
| specified for -- while still being understandable by the next
| guy. This nearly always means things are a bit oversized and
| inefficient to account for the things that the simple models
| are missing.
|
| Almost everything in engineering is like this, not just
| heating. It's pretty rare that something is fully optimised.
| ajolly wrote:
| I'd like more details on your home assistant setup as I'm
| trying to optimize mine.
|
| Btw, you can use $5 LYWSD03MMC thermometers with ble or zigbee.
| KennyBlanken wrote:
| > We've moved to an new apartment (house) and we had to do a
| full renovation. It doesn't have modern insulation and I
| calculated that for the time being the ROI on insulation isn't
| worth it.
|
| You calculated wrong, guaranteed. Most likely, you wildly
| underestimated fuel/electricity costs.
|
| > After spending a few hours of understanding the setups that
| "experts" have recommended, I figured out edge cases where they
| would be either wasteful or uncomfortable (meaning: unnecessary
| and inavoidable temperature overshoots or undershoots, etc.).
|
| Instead of thinking "the entire HVAC/heat industry are idiots
| who can't do any of this right", maybe you should take a look
| in the mirror and consider that your assumptions and/or
| criteria are wrong.
|
| For example: under/over shoots in a modern HVAC or heating
| system will not cause any "waste" or discomfort. 1-2 degree F
| in overshoot does not mean the space will lose appreciably more
| heat than if it had perfectly regulated at the setpoint. You
| also don't want a system that responds instantly. Let's say you
| open the door to receive a package, and you're signing
| paperwork, etc. You close the door. The air in the room is
| substantially cooler.
|
| Should the heat turn on?
|
| I bet it does in your home...but the correct answer is no,
| because the air will warm up rapidly from all the objects that
| were at the temperature of the room. Thousand-plus square feet
| worth of surface area...
| quickthrowman wrote:
| > I could not have been more wrong. After spending a few hours
| of understanding the setups that "experts" have recommended, I
| figured out edge cases where they would be either wasteful or
| uncomfortable (meaning: unnecessary and inavoidable temperature
| overshoots or undershoots, etc.). I had many-many rounds with
| Honeywell, Tado, Siemens, etc. and every single one of them had
| _major_ issues.
|
| Temperature hysteresis is unavoidable with a conventional
| thermostat, but you can reduce it with PID controllers. Most
| commercial building automation systems use PID controllers
| extensively.
|
| My guess is that the residential options from Honeywell, JCI,
| Siemens, Trane, Carrier, etc are focused more on one-size-fits-
| all applications, whereas commercial BAS systems are more or
| less bespoke designs for a specific building (using commodity
| sensors and controllers). I work with all five of the
| aforementioned companies on building automation projects, FWIW.
| rsynnott wrote:
| Some risk of collateral damage in the form of randomly
| controlling other peoples' boilers if your transmitter turns out
| to be more powerful than the one in the thermostat, tho...
| frontlodjkgi wrote:
| I imagine even encrypted messages could be replayed if the
| protocol wasn't designed against it. It also doesen't say what
| kind of encryption it uses, it could be a very weak in-house
| "encryption", for all we know it could be only an unknown
| encoding.
| videah wrote:
| The thermostat is paired with the boiler, the signals bundle
| the unique ID's of each so this won't happen. Otherwise there
| would be a risk the original thermostat would do the same.
| robocat wrote:
| > sledgehammer approach
|
| A hammerier solution would be to control the temperature seen by
| the thermostat (ignore the difficult RF protocol).
|
| A heating element and a temperature reading could control the
| heat seen by the thermostat.
|
| I'm pretty sure you wouldn't need any cooling (Peltier or
| whatever). Just a heater and ambient cooling! Set the thermostat
| to a high temperature, and run the heater to make the measured
| temperature hotter: when you don't want the heating to run.
|
| That said, I think hacking the RF protocol is geekier and far
| awesomer.
| gRoberts84 wrote:
| I went through various stages of this myself and got an Sonoff RF
| Bridge, that allowed me to capture and replay RF via Home
| Assistant. In the end though, it was always easier to use an off
| the shelf solution, especially for boilers. OpenTherm with Tado
| worked perfectly.
| gcanyon wrote:
| It's an awesome hack!
|
| It seems like the easier hack would be to put a peltier
| heater/cooler under the thermostat then control _that_ remotely
| to assume control over what temperature the thermostat sees.
|
| The link to the exact model of thermostat isn't working, so I
| don't know how amenable its design is to this approach, but the
| thermostats I've used are generally wall-mounted and putting a
| heat/cool source under them wouldn't be too hard. You'd need to
| make sure that you didn't send both the heat and cool into the
| thermostat, but that's a simple positioning problem.
| paulkrush wrote:
| Cool idea! It's ironic that this is such an efficient use case
| for device that is so inefficient.
| catsma21 wrote:
| yeah i put mine in the freezer
| looofooo0 wrote:
| Actually the best control system for such a boiler would be to
| control the heating curve where heating water temperature is
| fixed to the outside temperature. If you aim for the lowest
| water temperatures possible, then the system will become quite
| slow reacting. Then you only need to adjust the flow of water
| to the individual rooms to fix varying temperature issue. But
| this is long term manual optimization process which takes 1 to
| 2 years to perfect.
| gwbas1c wrote:
| > The only thing I'm not happy with is needing to use a very
| powerful and versatile radio like the HackRF for something as
| simple as a boiler on/off switch. But I'd rather use something
| overkill and have it work than spend ages trying to force smaller
| radios to do my bidding.
|
| All the apartments I lived in had basic thermostats; and I even
| rewired and replaced one of them.
|
| What was blocking Videah from buying an off-the-shelf thermostat?
| simooooo wrote:
| I've got a similar problem, and plan to replace the thermostat
| with a Shelly relay which can be toggled by home assistant's
| events based on the TRVs in each room.
|
| Then the boiler is basically controlled by the relay.
| aboardRat4 wrote:
| In the former Soviet Union we just have central heating
|
| The government maintains indoor temperature at 24 degrees from
| October to May, and the water is heated at the power stations.
| jobs_throwaway wrote:
| Jesus that sounds miserable. Sleeping at 75F?!
| MisterTea wrote:
| Instead of attacking a radio controlled relay, the author should
| have read up on how their heating system works. All they need is
| a relay controlled by an internet connected thing to replace the
| thermostat receiver. I could understand if the receiver was
| locked away but the video clearly shows they have access to the
| boiler.
| wpietri wrote:
| That leaves very visible evidence that things have been hacked.
| Any time the landlord comes around you'd want to remove that.
| And if there's some sort of infrastructure emergency (plumbing
| problem, heat goes out, fire in the building) it could be very
| challenging to get there and remove all traces before the
| landlord is stomping around.
| MisterTea wrote:
| Why would you be that paranoid? What laws exist in the UK
| where this is so illegal as to be that paranoid?
|
| That's a level of paranoia I would never have. You can easily
| conceal them in a way that is almost imperceptible.
| epsilonaurigae wrote:
| OP removed their comment section, but if you're here:
|
| I haven't done this since 2014 but the google nest API used to
| (hopefully still does?) let you see and or set the thermostats
| status with curl commands.
|
| My use case was to run one shell script that got my burglar
| alarms status, and if it was "armed/away" to simply set my nest
| thermostat as away, too.
|
| But it can also be hooked up to a dummy load or a relay and just
| used as an indoor temperature sensor.
|
| And the curl commands OP is relying on can be tied in to indoor
| and outdoor temperatures , such as scraping local weather with
| curl/wget and based on that integer, turning the boiler to a
| minimum when it's a certain temperature outside.
|
| Or turning it completely off when it's warm outside.
|
| I'm about to revisit this again just because I have an ancient
| gas pig of a furnace that uses microvolt and is too cold when
| it's cold outside, and too hot when it's warm outside.
|
| So I need one thermostat in place to turn it on no matter what at
| 40F, but then some conditional logic to kick that thing on and
| off on different cycles based on outdoor temps. The whole systems
| too crude to implement one off the shelf without adding a zone
| controller, so I just want a Linux box at home to be the zone
| controller....
|
| where I differ is that I'm not sending an RF signal to the
| boiler, I just have to close an NO contact to engage mine (and
| I'm lazily going to use the nest for that.)
|
| If anyone knows of a better thermostat that has its own API I can
| set, read sensors, turn hvac on and off without using google/nest
| account or having a dependency on the goodwill of their API
| existing forever , I'll come back and glean any responses thanks
| in advance.
|
| As an afterthought, hm I can just attach temperature probes and a
| GPIO for a relay and indoor/outdoor temps and do away with
| google/nest altogether.... Thanks for jogging my brain a bit I
| might do exactly that.
|
| (The nest was cool , and educational, I guess, 12 years ago when
| I didn't know how to really do anything but run and fire off curl
| commands on someone else's hardware for temp sense and closing a
| relay and I don't have anything bad to say about it as a starting
| point.)
|
| Where I was going with this , though, was that , you could use an
| off the shelf nest , and run
|
| 1) one command against API to get thermostat status (system
| thinks it's on or off , even though it's factually not directly
| controlling anything) and then based on that,
|
| 2) another command to your RF board to transmit a matching
| signal.
|
| ...
|
| (However you could also do the same with a temperature probe that
| can be read on board or over WiFi , and then manage your
| setpoints in the script and or by other means: eg scraping a
| weather site for the local outdoor temp in your case where the
| landlord probably wouldn't let you attach or connect an outdoor
| probe.)
|
| Bonus with the nest approach is you get a dial, can mount it on
| anything , doesn't have to be the wall of your unit... and it
| "sort of works" like a normal thermostat as well, as soon as the
| shell script reconciles the two states manually.
|
| Long winded rant but the original use case was an apartment where
| the thermostat was proprietary and serialized data and I didn't
| have any option to integrate a smart thermostat other than
| turning it to its maximum set point and then using the nest with
| a massive 220V/50A HVAC relay to just chunk the AC power line on
| and off on demand.
| josefritzishere wrote:
| For a related hack... If your apartment building with a BACnet
| system, it also relies on a set of commands for heating and
| cooling. Assuming you are on the same VLAN as teh server, you can
| inject commands. The difficulty is that every BACnet server is
| somewhat different, though most have spec online.
| ambalangoda wrote:
| I just gotta say, I really like the animated gifs. Kudos to the
| blogger.
| KennyBlanken wrote:
| What is with this absurd headline? Imitating your RF thermostat
| isn't "attacking" anything.
| mattmaroon wrote:
| I would probably just go about this by heating/cooling the
| thermostat itself rather than messing around with radio signals.
| Put a little box around it and something that could control the
| temp in the box, like a little peltier element. When you want the
| heat to run, cool the inside of the box. When you want it to
| stop, warm it up. Etc.
|
| But then I build thermal control devices for fun so maybe it just
| seems like a much easier method to me.
| pards wrote:
| X-10 devices [0] that do this have been around for a long time.
| I've even seen elaborate setups that can be controlled via a
| landline.
|
| [0]: https://thex10shop.com/products/x10-powerhouse-
| th2807-thermo...
| pete1302 wrote:
| Men in Black suit knocking on the door for this is a First-world
| thing.
| tgtweak wrote:
| I would have put a peltier/TEC below the thermostat to influence
| it's measured air temp vs resorting to reverse engineering and
| illegal signal broadcasting.
| noncovalence wrote:
| If I understood the OP correctly, then the broadcasting would
| only be illegal in the US.
| jorisboris wrote:
| I need this solution
|
| Our landlord installed a Honeywell home, the cheapest version,
| and it has no remote or timer capabilities
|
| And especially in winter it would be nice if it would jump on
| before we wake up!
| xbar wrote:
| The UK's Online Safety Act is pretty horrific. Our friends in the
| UK have my sympathy.
| lenerdenator wrote:
| > Please do your due diligence and check local laws before
| attempting anything I do in this post. Transmitting radio signals
| can become legally problematic very quickly, and the band I
| specifically transmit on here (868Mhz) is illegal in the United
| States without a license. I'd rather you didn't have men in suits
| knocking on your door on my account. You've been warned!
|
| Let's be honest here: the FCC is gonna have to see a _helluva_
| lot of problems coming from your transmissions before they bother
| to send the black Suburbans filled with men in suits to knock on
| your door. You 're going to get a series of letters that
| basically say "please don't do that" if anything.
| johnwalkr wrote:
| An American thermostat would be using around 920MHz which is
| the equivalent unlicensed band in the US. Funnily enough, the
| author warns Americans as an example but he is running more
| foul of the local rules an American would be (assuming an
| American would use 920MHz and not 868MHz).
|
| In the US you are allowed to tinker around there with home-
| built RF devices for personal use and prototyping in unlicensed
| bands, to some extent. Although, using an SDR for this requires
| a certain interpretation of the rules. In Europe it's basically
| not allowed, one shall only use pre-certified modules. Or only
| use the device you've built in an RF anechoic chamber until
| you've undertaken the certification process (totally
| impractical for a hobbyist).
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