17 ms·

200-year old heat pump technology is back

260 points by HR01 4y ago

hasmanean 4y ago
Now if only the worked on reducing the capital cost of the heat pump itself.
- YZF 4y ago
  If you're in Canada you can get more than half your cost back through federal and provincial grants... So it actually ends up being a pretty sweet deal.
aaron695 4y ago
[dead]
bamboozled 4y ago
Purchasing for our new place today.
- YZF 4y ago
  Presumably not the new idea that is discussed in the article though? We bought a heat pump last year and we're pretty happy with it. The cost is comparable to our older (not very efficient) gas furnace. Temperatures here (Vancouver, BC) rarely dip below zero Celsius.
- freitzkriesler2 4y ago
  I have a Bosch BBVA (with auxillary heat strips) that was installed a few months ago that replaced an air exchanger from 1971 and a roof compressor from the early 90s. I absolutely LOVE the Bosch system. It somehow manages to keep the heat more consistent at the set temp than my previous system. The Bosch system supposedly has some sort of power saving feature. We shall see how it handles the California summer. As the adage goes, install quality is more important than the unit itself but so far I'm really impressed with the Bosch unit.
rohan_ 4y ago
Every HVAC company I've talked to in Houston has advised me against heat pumps. Mainly, natural gas is so cheap in Texas that the cost benefit analysis doesn't work out.
- msandford 4y ago
  If you need to replace your AC anyhow it probably makes sense to go for a heat pump unit vs just AC. But it probably doesn't make sense to throw away an otherwise fine AC to upgrade. I say this as a Houstonian myself.
  - ilyt 4y ago
    I wonder if there is business to be made refitting old AC units to work in reverse. In theory only difference is some piping/valves.
    - infecto 4y ago
      Highly doubt it. The labor cost would probably exceed any savings and at the end of the day tech changes quick enough that you don't really want to be doing large service repairs on ac units, most likely more cost effective to replace the unit.
    - thehappypm 4y ago
      Interesting idea, but they have pretty short lifespans
- xt00 4y ago
  I would assume you have an AC unit as well as a gas furnace — but the AC unit is super close to just being a heat pump, so it’s worth considering replacing your AC unit with a heat pump at some point and turning off the gas furnace to see how the costs differ. Most likely for fairly long sections of the year in Texas you would easily heat your house with a heat pump at a low power usage since it’s not too cold out.
  - 4y ago
ximeng 4y ago
https://news.ycombinator.com/item?id=34397715 https://news.ycombinator.com/item?id=34397715 Recently discussed
- dredmorbius 4y ago
  Same article as well, published on multiple sites.
sushiburps 4y ago
Highly recommend the YouTube channel 'Technology Connections' videos on heat pumps: https://youtu.be/7J52mDjZzto https://youtu.be/7J52mDjZzto https://youtu.be/MFEHFsO-XSI https://youtu.be/MFEHFsO-XSI https://youtu.be/7zrx-b2sLUs https://youtu.be/7zrx-b2sLUs https://youtu.be/43XKfuptnik https://youtu.be/43XKfuptnik
- petepete 4y ago
  Technology Connections provides a great intro, Urban Plumbers is where you want to go for a more hands on, practical approach. https://youtube.com/@UrbanPlumbers https://youtube.com/@UrbanPlumbers
  - chongli 4y ago
    I’m not sure about where you live but where I live (Canada) you can’t legally do your own heat pump installations. You need to be certified to handle refrigerants and that sort of thing.
    - hn_go_brrrrr 4y ago
      Could you install the ones that come with precharged linesets?
      - chongli 4y ago
        Yes, for example a mini split unit. You can purchase these at the hardware store and install them yourself. You just can’t do this with units that integrate into a central heating/cooling system which require the installation and charging of the refrigerant lines.
    - petepete 4y ago
      I'm from the UK. I was under the impression you could do it yourself here but couldn't find a definitive answer. It's absolutely something I wouldn't take on myself though. Changing a light switch or rewiring a plug, sure - but I'd be guaranteed to make a huge, expensive, inefficient mess with a project like that.
nemo44x 4y ago
> Palmer has a heat pump in her U.S. home, along with a furnace as backup. “If it gets really cold, we can rely on the furnace,” she says And boom, there’s the problem. I have a heat pump for some bedrooms on the second floor but only because I have furnaces heating the other side. I am impressed how the tech has improved though.
- ilyt 4y ago
  I wonder if it would be economical to make ground-fed heat pump that had piping built in together with house (dig out foundation, put piping for water-to-water heat pump, build house), for the colder places.
  - __MatrixMan__ 4y ago
    I'm told that (at least for the soil near my house) you want the ground source piping to make it down to the ground water because without that moisture the soil's capacity to transmit heat degrades over time.
  - cyberax 4y ago
    You really need to tap into a watertable for the ground-loop to work. Otherwise it'll be nothing but a huge PITA. And at this point in time, the best air-source heat pumps are good enough until -25C. Meaning that you get CoP more than 1 at this temperature. So this would work for most of the US just fine.
    - wood_spirit 4y ago
      I have a “ground source heat pump” (a long pipe zig zagging under my lawn at about 2-3 foot depth) and kinda sandy soil and nobody mentioned no water table and it works great. Sand is not ideal but it’s not a blocker. The most common heap pumps use bore holes straight down into the rock here in Sweden, but lateral installs are marginally better performance (sun reheats soil every summer) if you have a big garden. Heap pumps dominate in Sweden so the installers have a lot of confidence and give good practical advise.
  - 4y ago
willnonya 4y ago
This paints heat pumps in a very rosey shade. The reason for heat pumps poor adoption is their poor performance and general inability to maintain comfortable Temps in colder climates and anywhere that weather and Temps change frequently. They also have a tendency to be unreliable. In an era where most home appliances have become less reliable, not more it is difficult to believe heat pumps would be the exception.
- montjoy 4y ago
  As the owner of a 20 year old heat pump in Minnesota I disagree. It does great for the temp range it’s programmed to run in.
  - superkuh 4y ago
    As a renter of a home with a ground loop buried heat pump in Wisconsin I was very disappointed in winter. It was cold inside and there was no way to keep it warm. I wouldn't rent another house with a heat pump.
    - hn_go_brrrrr 4y ago
      Your unit was undersized for the load. It's no different than having a too-small furnace.
      - superkuh 4y ago
        Just my point. Many builders over-estimate the efficiency of a heat pump when deploying the systems in places where it's -15F for months at a time and the frost line is 60 inches down. The label rating isn't going to be achieved. That can be fixed in time with better heat pumps made for actually cold places but right now there are still early adopter problems that don't apply to traditional furnances/heating.
    - montjoy 4y ago
      Aha. Yes I just have the above ground type. The only person I’ve met with an in-ground type wasn’t satisfied with his either but I figured that was because he was retrofitting it into an older home.
KyeRussell 4y ago
Whenever anything related to heat pumps comes up, it always feels necessary for me to point out how behind the times the US is. There are plenty of US climates that’d do just fine with a modern heat pump system. This wasn’t always the case admittedly, due to the lower lows. I know it’s a meme at this point, but even on HN I still see a lot of distinctly American ignorance and exceptionalism when people talk about this. I’m thankful for Technology Connections et al for putting the hard yards into getting some nerd circles across the line.
- 1123581321 4y ago
  Why does it feel necessary when you recognize that the technology has only recently become performant enough for mass adoption on a continent with a different general weather pattern?
pornel 4y ago
I've installed Vaillant air-to-water heat pump a year ago, and it has worked flawlessly so far (in the UK). Valliant's pump is pretty quiet (I've heard PCs with worse fans) and uses a relatively benign refrigerant.
- microtonal 4y ago
  We have a Nibe F470 air-to-air. Most of the time it's as loud as an old fridge. Not something you notice, since it in its own small room (where the gas furnace used to be). When it's freezing outside and the heat pump is working hard, it is louder, but you'd also hear the gas furnace under such circumstances. I think by and large, it's more quiet than the gas furnace we had before.
micro_cam 4y ago
We are running a large single head Mitsubishi ductless h2i in Montana. It easily provides most of our heating needs down to about -5F and some heat down to -15F, we have our old propane boiler / in floor system that kicks on when its really cold. And it provided ac in the summer which we didn't have previously. There are some downsides, it was expensive to put in and the outdoor unit is loud. While it does save us money, it probably wouldn't make sense as something that will pay for itself in heating costs with current propane prices and natural gas is much cheaper if you can get it. But definitely makes sense for new construction especially when paired with a wood or propane stove for back up heat in power outages/ambiance/quick heating.
- TEP_Kim_Il_Sung 4y ago
  Erect sandbags around your unit, leaving about 4' or enough for servicing. Make it 2 bags wide, and 4 bags higher than the unit. This will turn the noise into a slight murmur.
  - spikej 4y ago
    There must be a more aesthetically pleasing option...
    - OJFord 4y ago
      As a Briton not used to these things at all, I would think surrounding it in sandbags is the more aesthetically pleasing option.
      - jfk13 4y ago
        As a Briton, I can't help thinking that once the unit is in place, with its double-wall sandbag enclosure (including 4' service space), I won't have any garden left.
        sirmike_ 4y ago
        Why bother building the other three walls? Wouldn’t one SB wall between the unit and the exterior wall of the building cut down the noise enough?
Scene_Cast2 4y ago
I'm currently looking into getting a heat pump. Gree units seem both advanced and lower cost, so I'm trying to figure out if their quality is up to par. Does anyone know if heat pump outdoor units are audible?
- YZF 4y ago
  Well, they make some noise, but not as much as you'd think. I'm pretty sure that is on the spec of the various units so you can compare. We got a TOSOT and it's right out my office window but I can barely hear it (the indoor fan portion makes more noise in the house).
- briHass 4y ago
  It's going to depend on the model/manufacturer. Typically, the inverter based outdoor compressors are much quieter than the single or dual stage compressors that were common with the traditional American brands. If you can find the detailed spec sheet or service manual for the unit, they usually have decibal ratings listed.
- nelox 4y ago
  It would depend on the unit, but modern Japanese makes such as Daikin, Mitsubishi and Fujitsu are exceptionally quiet. I installed a Daikin multi-split system 10 years ago. My neighbour was concerned about the potential noise from the outdoor compressor. I assured her that it would not be possible to hear it from next door. On the final day of installation, the units were tested at full capacity. My neighbour craned her head around the wall and asked when it would be turned on. She couldn’t believe it was running full tilt. She couldn’t hear it at all.
simpsond 4y ago
I replaced an old condenser and furnace with a 21 seer 5 head mini split system last summer. It’s much quieter and allows everyone to have their preferred temp. My biggest surprise was the efficiency. I have amp meters on my mains, and I thought something was wrong when we first turned it on. The old condenser was 32k btu and the new one was ~40k, but it consumes 30% the energy compared to the old unit on average. This is all for AC. As for heating, my electricity bill is higher as I replaced natural gas… but I have solar. Anyways, heat pumps are pretty awesome IMO. On a new build I’d look at geo thermal heat pumps. Still a lot of theoretical efficiency to gain with improvements.
- twothamendment 4y ago
  I have a ground source heat pump to heat and cool my home. If you can do it, it is the best system I've ever had. You've got to have enough room for the horizonal loop, or drill some wells. It is a bit expensive to put in, so I wouldn't do it unless you plan to live there long enough to recoup the costs. If I were to sell my house nobody would give me a dime extra for it.
  - OJFord 4y ago
    Well, I would! But I get the point, it's just chance of who's otherwise interested, and to actually get the amount extra they think it's worth you probably need two of them anyway.
    - twothamendment 4y ago
      The first house I built (designed, generaled and did a lot of the work) was super insulated. Selling it taught me that people just look at square footage and price. They aren't likely to know or care if is built better. It was eye opening. I got a taste of exactly why builders build crap homes. Building code is the minimum and they build to it for a reason. We are now friends with the people who bought it and several times they have thanked us for building it well. They didn't know what they were getting, but it is nice to see they appreciate it now - especially when the power is out and neighbors are crying about their cold houses and these lucky people are staying warm. My third and final build I built for me. I never plan to sell. Even when my kids are gone and I only need half the house it would be very hard to find something to downsize to that would cost me less per month than I pay now. Ground source is that good.
franckl 4y ago
If you are into heat pumps, our team at Airthium (YC S17) is building an industrial heat pump able to reach 1000℉. Most HP are limited to 360℉ so it is a big deal in terms of industrial heat decarbonization potential (3% of the world's CO2 emissions). See https://airthium.com https://airthium.com
- OJFord 4y ago
  For the curious non-American that's 538 & 182. Is that basically 'just' a different refrigerant (and whatever necessary engineering to cope with it)?
  - iamthemonster 4y ago
    In case you don't get a reply from the parent commenter, it is basically putting many heat pumps together. So one heat pump steps the temperature up a bit, and your next heat pump takes that warm fluid and bumps up its temperature and so on. You don't want to do large changes in temperature all in one go because it's inefficient - heat pumps love small temperature differences.
    - franckl 4y ago
      We dont use refrigerant and it is a single HP with a 930F lift (so huge temperature difference between source and sink temperature). It is more than a heat pump, it is a new Stirling engine architecture, so it can run in reverse (heat to electricity) with an exceptional efficiency
postscapes1 4y ago
Just as a heads up. Make sure you get a real pro to do the sizing on your unit. I put in two Mitsubishi H2i systems last year and have had some pretty insane energy bills due to sizing them too large (A general overview of why here: https://carbonswitch.com/heat-pump-sizing-guide/ https://carbonswitch.com/heat-pump-sizing-guide/) Once I get my solar in place I won't feel too bad about this, but for now has been a bummer as was expecting a real efficient beast.
- dtgriscom 4y ago
  Around here (NE USA) oversizing is common with furnaces; the attitude is "better safe than sorry" where "sorry" means "contractor gets called because furnace struggles in mid-winter". I replaced my old (95kBTU/hour output) forced-hot-water furnace and separate hot water heater with a condensing furnace about eight years ago. I got a heat loss calculation done, which concluded I only needed 59kBTU/hr of heat. It was a struggle to get a small-enough furnace installed; one contractor said he couldn't in good conscience sell me anything smaller than 120kBTU/hr. My final system was 89kBTU/hr. A couple of weeks ago, in record -13°F/-25°C cold and high winds, it was burbling along at 60% power. Could have been even smaller.
  - bradfa 4y ago
    We had an energy audit done a few years ago and the conclusion was that we needed about 40kBTU/h of furnace (upstate NY). We have an 80 (came with the house when we bought it). It’s actually quite hard to buy any gas furnace smaller than 60. But modulating gas furnaces seem to be becoming a thing now which is good and may make up for over sizing.
- nicpottier 4y ago
  If you are oversized you may also run into problems of short cycling in warm weather, where you won't be able to dehumidify because it will be cooling too quickly. Who installed your system, they should be on the hook to fix it.
- thehappypm 4y ago
  The article doesn’t make it seem like oversizing is a problem for efficiency —- it will just cause the units to turn off more frequently, leading to other issues.
up2isomorphism 4y ago
The no 1 obstacle in us adopting heat pump is the installation cost, currently there is no way you can recuperate the initial cost of replacing gas furnace with a mini split, because you can get billed 10k in labor for a 1.5 day work even the equipment itself cost only 2k. You can not just send people checks and expect things can go well.
- tguvot 4y ago
  There are DIY mini-split systems that require only a couple of wrenches and drill. Installed one myself in garage last year. Only paid to electrician to run 240v
  - fomine3 4y ago
    You should use vacuum pump to avoid emitting GHG
    - tguvot 4y ago
      there is nothing to vacuum in diy systems. wall and outdoor units come pre-vacuumed and all the refrigerant is in lineset
      - fomine3 4y ago
        I didn't know that pre-charged refrigerant lines is a thing. I wonder how they purge air.
        tguvot 4y ago
        wall unit and outdoor unit come pre-vacuumed and sealed. lineset filled with gas and sealed. when you connect lineset to units seals are broken and gas fills entire system.
  - up2isomorphism 4y ago
    The same reason can be asked why not just buy a couple hard drives and a server instead of going to cloud, because most people can not do much beyond their professions.
japanman425 4y ago
[dead]
pontifier 4y ago
I have the feeling that the next big thing we're going to see is cheap and easy ways to very effectively insulate old buildings. Then you won't need to heat or cool them very much at all.
seaghost 4y ago
We have recently bought newly built 2 story house (140m2) with the heat pump and foor heating completely insulated. Our electricity consumption is 600 KWh per month including heating end everything else. We keep thermostat at 20 degrees centigrade. Is the consumption too high or normal for the house of this size and configuration?
- ThePowerOfFuet 4y ago
  Nearly €120 a month for electricity sounds like quite a lot, but I don't know what's common for standalone houses.
- enjikaka 4y ago
  Depends on the outside temp too. Best to monitor SCOP. My 180 m2 house with 18 degrees inside in January w ground souce heat pump (IVT Geo 508) and normal radiators -> - SCOP: 3.88 - kWh used: 525 kWh - kWh produced: 2034.8 kWh - Outside min: -11.4 - …max: 5.65 - …mean: 0.3
- cujaneway 4y ago
  That sounds about right if you've got the thermostat at 20 degrees constantly; I live in a 700~ sq ft apartment and consume around 300kwh/pm; 10% of that is an inefficient NAS I built from old parts and I hardly use the heaters because god almighty are electric heaters inefficient.
- orwin 4y ago
  Assuming you are in western Europe, I'd say for 140m2 it seems a bit more than okay, depending on how much windows you have. And depending how north you are. And depending on your usage (WFH, cooking...), it can be great.
  - seaghost 4y ago
    I do have 9 windows, living room is the sliding one which is 2,5x4 meters. I rarely work from home, cooking almost every evening.
manmal 4y ago
If we want to move the needle in a meaningful way (CO2 wise), heat pumps and solar panels need to get better, cheaper, easier to install, and more available. Where I live, driving a heat pump is more expensive than burning gas, from a purely economical POV. Our cost ratio per kW/h for electricity:gas is 3.5:1 right now, but COP for consumer heat pumps in real-world usage is just 2.6 (Yeah they all claim a COP of at least 3, but those are as realistic as ICE fuel economy ratings.) Those ratios need to at least match in order for a heat pump to make any kind of financial sense. Those heat pumps for a mid sized house cost €15k right now. On back order for 12+ months.
- teruakohatu 4y ago
  A real world mean COP of 3.5 is not unusual, see this paper: https://www.sciencedirect.com/science/article/pii/S0378778821006496 https://www.sciencedirect.com/science/article/pii/S037877882... Gas isn't 100% efficient either in heating the home. Boilers are ~92%.
  - manmal 4y ago
    A German consumer report mentioned 2.6 (can’t find it right now), maybe that’s owed to Germany‘s climate.
- adam_arthur 4y ago
  Using a heatpump likely actually worsens CO2 impact, as most utilities providing the electricity don’t run on green energy. E.g. you can either burn natural gas directly, or use electricity the Utility generated by burning natural gas. Or even Coal in many cases. But that’s speaking more to the impact today. In the long run electrification across the board is required to reduce emissions.
  - manmal 4y ago
    Really depends on where you live. In Austria, it’s cleaner to use a heatpump.
    - 4y ago
tony-allan 4y ago
I liked this explanation video the best: https://youtu.be/watch?v=-vU9x3dFMrU https://youtu.be/watch?v=-vU9x3dFMrU Ref: https://yaleclimateconnections.org/2023/02/how-heat-pumps-of-the-1800s-are-becoming-the-technology-of-the-future/ https://yaleclimateconnections.org/2023/02/how-heat-pumps-of...
peterclary 4y ago
What is the impact on the immediate local environment? Drawing the heat out of the ground throughout the year surely means the ground will be colder going into winter. What impact does that have on plants, insects and small mammals when they are overwintering in the ground, etc? And what is the knock-on effect from that?
- rightbyte 4y ago
  I have never heard this to be a problem for classic water water heatpumps. The hole goes straight down so the area impacted is quite small and the first part is isolated anyways. Dunno how far down insects and mouses live? In the article they mention heating the ground with 1.5m deep holes. I guess that would annoy the local life?
- ttyprintk 4y ago
  I’ve heard horizontal heat exchangers can freeze the soil. Grass is expected to be fine, but tree roots might reach.
bob_theslob646 4y ago
The only problem would he pumps that I've heard is that you have to apparently get a water filter here in the United States because depending on the water quality it could do tremendous damage to the HVAC system if it's not treated and that can be very expensive. The treatment part not the replacement part. Obviously that's expensive
jonkratz 4y ago
This guy is doing something similar with heat pumps and water storage - specifically utilizing radiator and boiler along with heat pumps: https://www.2040energy.com https://www.2040energy.com
- voidee 4y ago
  Following! Thanks for the link.
Maursault 4y ago
> The British mathematician, physicist and engineer Lord Kelvin proposed using heat pump systems for space heating way back in 1852. As Lord Kelvin didn't become Lord Kelvin until 1892, it was thus a young, 28yo Professor William Thompson that made this proposal.

260 points by HR01 4y ago

hasmanean 4y ago

Now if only the worked on reducing the capital cost of the heat pump itself.

YZF 4y ago
If you're in Canada you can get more than half your cost back through federal and provincial grants... So it actually ends up being a pretty sweet deal.

aaron695 4y ago

[dead]

bamboozled 4y ago

Purchasing for our new place today.

YZF 4y ago
Presumably not the new idea that is discussed in the article though? We bought a heat pump last year and we're pretty happy with it. The cost is comparable to our older (not very efficient) gas furnace. Temperatures here (Vancouver, BC) rarely dip below zero Celsius.
freitzkriesler2 4y ago
I have a Bosch BBVA (with auxillary heat strips) that was installed a few months ago that replaced an air exchanger from 1971 and a roof compressor from the early 90s. I absolutely LOVE the Bosch system. It somehow manages to keep the heat more consistent at the set temp than my previous system. The Bosch system supposedly has some sort of power saving feature. We shall see how it handles the California summer. As the adage goes, install quality is more important than the unit itself but so far I'm really impressed with the Bosch unit.

rohan_ 4y ago

Every HVAC company I've talked to in Houston has advised me against heat pumps. Mainly, natural gas is so cheap in Texas that the cost benefit analysis doesn't work out.

msandford 4y ago
If you need to replace your AC anyhow it probably makes sense to go for a heat pump unit vs just AC. But it probably doesn't make sense to throw away an otherwise fine AC to upgrade. I say this as a Houstonian myself.
- ilyt 4y ago
  I wonder if there is business to be made refitting old AC units to work in reverse. In theory only difference is some piping/valves.
  - infecto 4y ago
    Highly doubt it. The labor cost would probably exceed any savings and at the end of the day tech changes quick enough that you don't really want to be doing large service repairs on ac units, most likely more cost effective to replace the unit.
  - thehappypm 4y ago
    Interesting idea, but they have pretty short lifespans
xt00 4y ago
I would assume you have an AC unit as well as a gas furnace — but the AC unit is super close to just being a heat pump, so it’s worth considering replacing your AC unit with a heat pump at some point and turning off the gas furnace to see how the costs differ. Most likely for fairly long sections of the year in Texas you would easily heat your house with a heat pump at a low power usage since it’s not too cold out.
- 4y ago

ximeng 4y ago

https://news.ycombinator.com/item?id=34397715 https://news.ycombinator.com/item?id=34397715 Recently discussed

dredmorbius 4y ago
Same article as well, published on multiple sites.

sushiburps 4y ago

Highly recommend the YouTube channel 'Technology Connections' videos on heat pumps: https://youtu.be/7J52mDjZzto https://youtu.be/7J52mDjZzto https://youtu.be/MFEHFsO-XSI https://youtu.be/MFEHFsO-XSI https://youtu.be/7zrx-b2sLUs https://youtu.be/7zrx-b2sLUs https://youtu.be/43XKfuptnik https://youtu.be/43XKfuptnik

petepete 4y ago
Technology Connections provides a great intro, Urban Plumbers is where you want to go for a more hands on, practical approach. https://youtube.com/@UrbanPlumbers https://youtube.com/@UrbanPlumbers
- chongli 4y ago
  I’m not sure about where you live but where I live (Canada) you can’t legally do your own heat pump installations. You need to be certified to handle refrigerants and that sort of thing.
  - hn_go_brrrrr 4y ago
    Could you install the ones that come with precharged linesets?
    - chongli 4y ago
      Yes, for example a mini split unit. You can purchase these at the hardware store and install them yourself. You just can’t do this with units that integrate into a central heating/cooling system which require the installation and charging of the refrigerant lines.
  - petepete 4y ago
    I'm from the UK. I was under the impression you could do it yourself here but couldn't find a definitive answer. It's absolutely something I wouldn't take on myself though. Changing a light switch or rewiring a plug, sure - but I'd be guaranteed to make a huge, expensive, inefficient mess with a project like that.

nemo44x 4y ago

> Palmer has a heat pump in her U.S. home, along with a furnace as backup. “If it gets really cold, we can rely on the furnace,” she says And boom, there’s the problem. I have a heat pump for some bedrooms on the second floor but only because I have furnaces heating the other side. I am impressed how the tech has improved though.

ilyt 4y ago
I wonder if it would be economical to make ground-fed heat pump that had piping built in together with house (dig out foundation, put piping for water-to-water heat pump, build house), for the colder places.
- __MatrixMan__ 4y ago
  I'm told that (at least for the soil near my house) you want the ground source piping to make it down to the ground water because without that moisture the soil's capacity to transmit heat degrades over time.
- cyberax 4y ago
  You really need to tap into a watertable for the ground-loop to work. Otherwise it'll be nothing but a huge PITA. And at this point in time, the best air-source heat pumps are good enough until -25C. Meaning that you get CoP more than 1 at this temperature. So this would work for most of the US just fine.
  - wood_spirit 4y ago
    I have a “ground source heat pump” (a long pipe zig zagging under my lawn at about 2-3 foot depth) and kinda sandy soil and nobody mentioned no water table and it works great. Sand is not ideal but it’s not a blocker. The most common heap pumps use bore holes straight down into the rock here in Sweden, but lateral installs are marginally better performance (sun reheats soil every summer) if you have a big garden. Heap pumps dominate in Sweden so the installers have a lot of confidence and give good practical advise.
- 4y ago

willnonya 4y ago

This paints heat pumps in a very rosey shade. The reason for heat pumps poor adoption is their poor performance and general inability to maintain comfortable Temps in colder climates and anywhere that weather and Temps change frequently. They also have a tendency to be unreliable. In an era where most home appliances have become less reliable, not more it is difficult to believe heat pumps would be the exception.

montjoy 4y ago
As the owner of a 20 year old heat pump in Minnesota I disagree. It does great for the temp range it’s programmed to run in.
- superkuh 4y ago
  As a renter of a home with a ground loop buried heat pump in Wisconsin I was very disappointed in winter. It was cold inside and there was no way to keep it warm. I wouldn't rent another house with a heat pump.
  - hn_go_brrrrr 4y ago
    Your unit was undersized for the load. It's no different than having a too-small furnace.
    - superkuh 4y ago
      Just my point. Many builders over-estimate the efficiency of a heat pump when deploying the systems in places where it's -15F for months at a time and the frost line is 60 inches down. The label rating isn't going to be achieved. That can be fixed in time with better heat pumps made for actually cold places but right now there are still early adopter problems that don't apply to traditional furnances/heating.
  - montjoy 4y ago
    Aha. Yes I just have the above ground type. The only person I’ve met with an in-ground type wasn’t satisfied with his either but I figured that was because he was retrofitting it into an older home.

KyeRussell 4y ago

Whenever anything related to heat pumps comes up, it always feels necessary for me to point out how behind the times the US is. There are plenty of US climates that’d do just fine with a modern heat pump system. This wasn’t always the case admittedly, due to the lower lows. I know it’s a meme at this point, but even on HN I still see a lot of distinctly American ignorance and exceptionalism when people talk about this. I’m thankful for Technology Connections et al for putting the hard yards into getting some nerd circles across the line.

1123581321 4y ago
Why does it feel necessary when you recognize that the technology has only recently become performant enough for mass adoption on a continent with a different general weather pattern?

pornel 4y ago

I've installed Vaillant air-to-water heat pump a year ago, and it has worked flawlessly so far (in the UK). Valliant's pump is pretty quiet (I've heard PCs with worse fans) and uses a relatively benign refrigerant.

microtonal 4y ago
We have a Nibe F470 air-to-air. Most of the time it's as loud as an old fridge. Not something you notice, since it in its own small room (where the gas furnace used to be). When it's freezing outside and the heat pump is working hard, it is louder, but you'd also hear the gas furnace under such circumstances. I think by and large, it's more quiet than the gas furnace we had before.

micro_cam 4y ago

We are running a large single head Mitsubishi ductless h2i in Montana. It easily provides most of our heating needs down to about -5F and some heat down to -15F, we have our old propane boiler / in floor system that kicks on when its really cold. And it provided ac in the summer which we didn't have previously. There are some downsides, it was expensive to put in and the outdoor unit is loud. While it does save us money, it probably wouldn't make sense as something that will pay for itself in heating costs with current propane prices and natural gas is much cheaper if you can get it. But definitely makes sense for new construction especially when paired with a wood or propane stove for back up heat in power outages/ambiance/quick heating.

TEP_Kim_Il_Sung 4y ago
Erect sandbags around your unit, leaving about 4' or enough for servicing. Make it 2 bags wide, and 4 bags higher than the unit. This will turn the noise into a slight murmur.
- spikej 4y ago
  There must be a more aesthetically pleasing option...
  - OJFord 4y ago
    As a Briton not used to these things at all, I would think surrounding it in sandbags is the more aesthetically pleasing option.
    - jfk13 4y ago
      As a Briton, I can't help thinking that once the unit is in place, with its double-wall sandbag enclosure (including 4' service space), I won't have any garden left.
      - sirmike_ 4y ago
        Why bother building the other three walls? Wouldn’t one SB wall between the unit and the exterior wall of the building cut down the noise enough?

Scene_Cast2 4y ago

I'm currently looking into getting a heat pump. Gree units seem both advanced and lower cost, so I'm trying to figure out if their quality is up to par. Does anyone know if heat pump outdoor units are audible?

YZF 4y ago
Well, they make some noise, but not as much as you'd think. I'm pretty sure that is on the spec of the various units so you can compare. We got a TOSOT and it's right out my office window but I can barely hear it (the indoor fan portion makes more noise in the house).
briHass 4y ago
It's going to depend on the model/manufacturer. Typically, the inverter based outdoor compressors are much quieter than the single or dual stage compressors that were common with the traditional American brands. If you can find the detailed spec sheet or service manual for the unit, they usually have decibal ratings listed.
nelox 4y ago
It would depend on the unit, but modern Japanese makes such as Daikin, Mitsubishi and Fujitsu are exceptionally quiet. I installed a Daikin multi-split system 10 years ago. My neighbour was concerned about the potential noise from the outdoor compressor. I assured her that it would not be possible to hear it from next door. On the final day of installation, the units were tested at full capacity. My neighbour craned her head around the wall and asked when it would be turned on. She couldn’t believe it was running full tilt. She couldn’t hear it at all.

simpsond 4y ago

I replaced an old condenser and furnace with a 21 seer 5 head mini split system last summer. It’s much quieter and allows everyone to have their preferred temp. My biggest surprise was the efficiency. I have amp meters on my mains, and I thought something was wrong when we first turned it on. The old condenser was 32k btu and the new one was ~40k, but it consumes 30% the energy compared to the old unit on average. This is all for AC. As for heating, my electricity bill is higher as I replaced natural gas… but I have solar. Anyways, heat pumps are pretty awesome IMO. On a new build I’d look at geo thermal heat pumps. Still a lot of theoretical efficiency to gain with improvements.

twothamendment 4y ago
I have a ground source heat pump to heat and cool my home. If you can do it, it is the best system I've ever had. You've got to have enough room for the horizonal loop, or drill some wells. It is a bit expensive to put in, so I wouldn't do it unless you plan to live there long enough to recoup the costs. If I were to sell my house nobody would give me a dime extra for it.
- OJFord 4y ago
  Well, I would! But I get the point, it's just chance of who's otherwise interested, and to actually get the amount extra they think it's worth you probably need two of them anyway.
  - twothamendment 4y ago
    The first house I built (designed, generaled and did a lot of the work) was super insulated. Selling it taught me that people just look at square footage and price. They aren't likely to know or care if is built better. It was eye opening. I got a taste of exactly why builders build crap homes. Building code is the minimum and they build to it for a reason. We are now friends with the people who bought it and several times they have thanked us for building it well. They didn't know what they were getting, but it is nice to see they appreciate it now - especially when the power is out and neighbors are crying about their cold houses and these lucky people are staying warm. My third and final build I built for me. I never plan to sell. Even when my kids are gone and I only need half the house it would be very hard to find something to downsize to that would cost me less per month than I pay now. Ground source is that good.

franckl 4y ago

If you are into heat pumps, our team at Airthium (YC S17) is building an industrial heat pump able to reach 1000℉. Most HP are limited to 360℉ so it is a big deal in terms of industrial heat decarbonization potential (3% of the world's CO2 emissions). See https://airthium.com https://airthium.com

OJFord 4y ago
For the curious non-American that's 538 & 182. Is that basically 'just' a different refrigerant (and whatever necessary engineering to cope with it)?
- iamthemonster 4y ago
  In case you don't get a reply from the parent commenter, it is basically putting many heat pumps together. So one heat pump steps the temperature up a bit, and your next heat pump takes that warm fluid and bumps up its temperature and so on. You don't want to do large changes in temperature all in one go because it's inefficient - heat pumps love small temperature differences.
  - franckl 4y ago
    We dont use refrigerant and it is a single HP with a 930F lift (so huge temperature difference between source and sink temperature). It is more than a heat pump, it is a new Stirling engine architecture, so it can run in reverse (heat to electricity) with an exceptional efficiency

postscapes1 4y ago

Just as a heads up. Make sure you get a real pro to do the sizing on your unit. I put in two Mitsubishi H2i systems last year and have had some pretty insane energy bills due to sizing them too large (A general overview of why here: https://carbonswitch.com/heat-pump-sizing-guide/ https://carbonswitch.com/heat-pump-sizing-guide/) Once I get my solar in place I won't feel too bad about this, but for now has been a bummer as was expecting a real efficient beast.

dtgriscom 4y ago
Around here (NE USA) oversizing is common with furnaces; the attitude is "better safe than sorry" where "sorry" means "contractor gets called because furnace struggles in mid-winter". I replaced my old (95kBTU/hour output) forced-hot-water furnace and separate hot water heater with a condensing furnace about eight years ago. I got a heat loss calculation done, which concluded I only needed 59kBTU/hr of heat. It was a struggle to get a small-enough furnace installed; one contractor said he couldn't in good conscience sell me anything smaller than 120kBTU/hr. My final system was 89kBTU/hr. A couple of weeks ago, in record -13°F/-25°C cold and high winds, it was burbling along at 60% power. Could have been even smaller.
- bradfa 4y ago
  We had an energy audit done a few years ago and the conclusion was that we needed about 40kBTU/h of furnace (upstate NY). We have an 80 (came with the house when we bought it). It’s actually quite hard to buy any gas furnace smaller than 60. But modulating gas furnaces seem to be becoming a thing now which is good and may make up for over sizing.
nicpottier 4y ago
If you are oversized you may also run into problems of short cycling in warm weather, where you won't be able to dehumidify because it will be cooling too quickly. Who installed your system, they should be on the hook to fix it.
thehappypm 4y ago
The article doesn’t make it seem like oversizing is a problem for efficiency —- it will just cause the units to turn off more frequently, leading to other issues.

up2isomorphism 4y ago

The no 1 obstacle in us adopting heat pump is the installation cost, currently there is no way you can recuperate the initial cost of replacing gas furnace with a mini split, because you can get billed 10k in labor for a 1.5 day work even the equipment itself cost only 2k. You can not just send people checks and expect things can go well.

tguvot 4y ago
There are DIY mini-split systems that require only a couple of wrenches and drill. Installed one myself in garage last year. Only paid to electrician to run 240v
- fomine3 4y ago
  You should use vacuum pump to avoid emitting GHG
  - tguvot 4y ago
    there is nothing to vacuum in diy systems. wall and outdoor units come pre-vacuumed and all the refrigerant is in lineset
    - fomine3 4y ago
      I didn't know that pre-charged refrigerant lines is a thing. I wonder how they purge air.
      - tguvot 4y ago
        wall unit and outdoor unit come pre-vacuumed and sealed. lineset filled with gas and sealed. when you connect lineset to units seals are broken and gas fills entire system.
- up2isomorphism 4y ago
  The same reason can be asked why not just buy a couple hard drives and a server instead of going to cloud, because most people can not do much beyond their professions.

japanman425 4y ago

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pontifier 4y ago

I have the feeling that the next big thing we're going to see is cheap and easy ways to very effectively insulate old buildings. Then you won't need to heat or cool them very much at all.

seaghost 4y ago

We have recently bought newly built 2 story house (140m2) with the heat pump and foor heating completely insulated. Our electricity consumption is 600 KWh per month including heating end everything else. We keep thermostat at 20 degrees centigrade. Is the consumption too high or normal for the house of this size and configuration?

ThePowerOfFuet 4y ago
Nearly €120 a month for electricity sounds like quite a lot, but I don't know what's common for standalone houses.
enjikaka 4y ago
Depends on the outside temp too. Best to monitor SCOP. My 180 m2 house with 18 degrees inside in January w ground souce heat pump (IVT Geo 508) and normal radiators -> - SCOP: 3.88 - kWh used: 525 kWh - kWh produced: 2034.8 kWh - Outside min: -11.4 - …max: 5.65 - …mean: 0.3
cujaneway 4y ago
That sounds about right if you've got the thermostat at 20 degrees constantly; I live in a 700~ sq ft apartment and consume around 300kwh/pm; 10% of that is an inefficient NAS I built from old parts and I hardly use the heaters because god almighty are electric heaters inefficient.
orwin 4y ago
Assuming you are in western Europe, I'd say for 140m2 it seems a bit more than okay, depending on how much windows you have. And depending how north you are. And depending on your usage (WFH, cooking...), it can be great.
- seaghost 4y ago
  I do have 9 windows, living room is the sliding one which is 2,5x4 meters. I rarely work from home, cooking almost every evening.

manmal 4y ago

If we want to move the needle in a meaningful way (CO2 wise), heat pumps and solar panels need to get better, cheaper, easier to install, and more available. Where I live, driving a heat pump is more expensive than burning gas, from a purely economical POV. Our cost ratio per kW/h for electricity:gas is 3.5:1 right now, but COP for consumer heat pumps in real-world usage is just 2.6 (Yeah they all claim a COP of at least 3, but those are as realistic as ICE fuel economy ratings.) Those ratios need to at least match in order for a heat pump to make any kind of financial sense. Those heat pumps for a mid sized house cost €15k right now. On back order for 12+ months.

teruakohatu 4y ago
A real world mean COP of 3.5 is not unusual, see this paper: https://www.sciencedirect.com/science/article/pii/S0378778821006496 https://www.sciencedirect.com/science/article/pii/S037877882... Gas isn't 100% efficient either in heating the home. Boilers are ~92%.
- manmal 4y ago
  A German consumer report mentioned 2.6 (can’t find it right now), maybe that’s owed to Germany‘s climate.
adam_arthur 4y ago
Using a heatpump likely actually worsens CO2 impact, as most utilities providing the electricity don’t run on green energy. E.g. you can either burn natural gas directly, or use electricity the Utility generated by burning natural gas. Or even Coal in many cases. But that’s speaking more to the impact today. In the long run electrification across the board is required to reduce emissions.
- manmal 4y ago
  Really depends on where you live. In Austria, it’s cleaner to use a heatpump.
  - 4y ago

tony-allan 4y ago

I liked this explanation video the best: https://youtu.be/watch?v=-vU9x3dFMrU https://youtu.be/watch?v=-vU9x3dFMrU Ref: https://yaleclimateconnections.org/2023/02/how-heat-pumps-of-the-1800s-are-becoming-the-technology-of-the-future/ https://yaleclimateconnections.org/2023/02/how-heat-pumps-of...

peterclary 4y ago

What is the impact on the immediate local environment? Drawing the heat out of the ground throughout the year surely means the ground will be colder going into winter. What impact does that have on plants, insects and small mammals when they are overwintering in the ground, etc? And what is the knock-on effect from that?

rightbyte 4y ago
I have never heard this to be a problem for classic water water heatpumps. The hole goes straight down so the area impacted is quite small and the first part is isolated anyways. Dunno how far down insects and mouses live? In the article they mention heating the ground with 1.5m deep holes. I guess that would annoy the local life?
ttyprintk 4y ago
I’ve heard horizontal heat exchangers can freeze the soil. Grass is expected to be fine, but tree roots might reach.

bob_theslob646 4y ago

The only problem would he pumps that I've heard is that you have to apparently get a water filter here in the United States because depending on the water quality it could do tremendous damage to the HVAC system if it's not treated and that can be very expensive. The treatment part not the replacement part. Obviously that's expensive

jonkratz 4y ago

This guy is doing something similar with heat pumps and water storage - specifically utilizing radiator and boiler along with heat pumps: https://www.2040energy.com https://www.2040energy.com

voidee 4y ago
Following! Thanks for the link.

Maursault 4y ago

> The British mathematician, physicist and engineer Lord Kelvin proposed using heat pump systems for space heating way back in 1852. As Lord Kelvin didn't become Lord Kelvin until 1892, it was thus a young, 28yo Professor William Thompson that made this proposal.