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A heat pump just makes no sense whatsoever for me in my northeast town. The electric bill alone would outpace the old propane bill, not to mention installation

A heat pump just makes no sense whatsoever for me in my northeast town. The electric bill alone would outpace the old propane bill, not to mention installation. And it won't even work during some of the coldest winter weeks when you _really_ need it to work. Maybe I would consider it if I was in, like, Nevada or somewhere.

corbet 1y ago
My heat pump, in Colorado, kept the house warm at -18°F last winter. Without firing up the backup resistance heating strip. I think it works. (It is more expensive to operate than the natural-gas furnace was, though).
- skywhopper 1y ago
  Insulation matters as well and I’m guessing your Colorado house is far newer and better sealed than most New England homes.
doctorhandshake 1y ago
The notion that heat pumps don’t work at low temperatures hasn’t been true for years. I think you may be surprised to find that just about any heat pump you look at has good efficiency down to very low temperatures.
- Loughla 1y ago
  Define low temperatures. Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps.
  - doctorhandshake 1y ago
    I’m not sure what yours is but it doesn’t sound appropriate to your application. Mitsubishi hyper heat is indicative of a contemporary inverter design - 100% efficiency to -5f: https://www.mitsubishicomfort.com/articles/mythbusters-heat-pumps-for-extreme-cold-climates https://www.mitsubishicomfort.com/articles/mythbusters-heat-...
    - sokoloff 1y ago
      100% efficiency is terrible for a heat pump. Electric resistance heat is 100% efficient.
      - doctorhandshake 1y ago
        I should have said 100% performance. COP is typically 3-4:1 with mitsu
        sokoloff 1y ago
        Typical seasonal average? Sure. At -5°F? Hell no! At +5°F, they rate their own equipment to have a 2.0 CoP. https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10007%5CM_SUBMITTAL_MXZ-4C36NAHZ2-en.pdf https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.c...
        throw0101a 1y ago
        Here's a Trane/Mitsubishi unit that has a COP of (at least) 3 at -13F/-25C: * https://ashp.neep.org/#!/product/156605/7/25000/95/7500/0///0 https://ashp.neep.org/#!/product/156605/7/25000/95/7500/0///... An LG unit with 2.4 at -4F/-20C: * https://ashp.neep.org/#!/product/29688/7/25000/95/7500/0///0 https://ashp.neep.org/#!/product/29688/7/25000/95/7500/0///0 Searchable database of cold climate air source heat pumps (ccASHPs): * https://ashp.neep.org/#!/product_list/ https://ashp.neep.org/#!/product_list/
        sokoloff 1y ago
        Correct (and thanks for the link to that unit). Though it’s worth noting that that first 2 ton rated unit is putting out 0.5 tons (6k BTU/hr) at that temp and rating. That’s not going to be particularly helpful for a structure that needed 24k BTU/hr during warmer temps, meaning the owner of the unit is likely mixing in a lot of 1.0 BTUs to meet the heat loss at -13°F.
  - crazygringo 1y ago
    I've got one about 8 years old, and it does just fine down to 0°F (it hasn't gotten colder than that here). It doesn't even have any kind of auxiliary heat. It's fine. The only difference when it's super-cold is that the air coming out of it isn't as warm, so the heating cycle stays on for a longer proportion of the time. But it keeps it 70°F inside no problem at all.
  - tzs 1y ago
    That's one of the older style units. Starting in 2007 when Mitsubishi introduced their "Hyper-Heating Inverter" heat pumps, and continuing with Fujitsu and Daikin following with similar technology in the 2010-12 timeframe, and others a few years later, heat pumps got way better in the cold. Mitsubishi's maintain 200%+ efficiency down to -4℉ (-20℃) and 150% down to -22℉ (-30℃) [1]. Only a few towns in the continental US get below that, and even those aren't going to get cold enough long enough to make it worth it an an all electric home to switch to your emergency electrical resistance heating. Their capacity doesn't start dropping until you get down to 23℉ (-5℃), dropping to 76% at -13℉ (-25℃). [1] https://www.coolingpost.com/world-news/study-proves-heat-pump-efficiency-at-low-temperatures/ https://www.coolingpost.com/world-news/study-proves-heat-pum...
  - throw0101a 1y ago
    > Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps. What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: * https://basc.pnnl.gov/images/iecc-climate-zone-map https://basc.pnnl.gov/images/iecc-climate-zone-map ASHRAE—an HVAC organization—has data on the coldest and hottest days for areas so that you can design things for the coldest or hottest 1% of the year (4 hottest/coldest days): * https://ashrae-meteo.info/v2.0/ https://ashrae-meteo.info/v2.0/ I think that if you have an older, leaky/ier, less-insulated house you may need to 'brute force' heating your (probably older) domicile. But if you have a <4 ACH@50 air tightness, and reasonable insulation levels, a good portion of the US population could make do with a heat pump. Mitsubishi publishes data were they have 100% heating capacity at -15C, which some models being 100% at -20C and -23C: * https://www.mitsubishielectric.ca/en/hvac/home-owners/zuba https://www.mitsubishielectric.ca/en/hvac/home-owners/zuba At -25C they have 80% capacity: * https://www.mitsair.com/wp-content/uploads/2024/10/MEM-202406-E_ZubaRebrandBroch_LR_FIN-1.pdf https://www.mitsair.com/wp-content/uploads/2024/10/MEM-20240...
    - whateveracct 1y ago
      > What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: A lot? e.g. Chicago gets it every year
      - throw0101c 1y ago
        >>> Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps. >> > What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: > A lot? e.g. Chicago gets it every year [citation needed] Per historical weather data: https://ashrae-meteo.info/v2.0/index.php?lat=41.960&lng=-87.932&place=%27%27&wmo=725300 https://ashrae-meteo.info/v2.0/index.php?lat=41.960&lng=-87.... It is warmer than -16C/3F at Chicago (O'Hare) for 99% of the time (i.e., except for 4 days a year), and warmer than -18.7C/-2F for 99.6% of the time (2 days). ASHRAE are the folks that publish the heating/cooling standards that are used in building codes for estimate heating/cooling equipment capacities (Manual J) and selecting the right equipment (Manual S). Here's a PDF with a lot of locations in the US and CA (and other countries further down), and if you look under the "Heating DB" column, you'll find very few US locations that have -30F under the 99% (or even 99.6%) sub-columns: * https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/winter_summer_design_temps_us.pdf https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/... So unless you're in AK, MN, or ND, long runs of temperatures colder than -20F/-30C don't happen too often. Of course if you have a leaky house with little insulation, you're throwing money out the window/door, so the first consideration for a good ROI is better air sealing and insulation.
- crgwbr 1y ago
  That’s true, but still doesn’t always make heat pumps the most cost effective choice to operate. For example, last winter I paid an average of $0.24/kWh for electricity vs $0.05/kWh for natural gas. Even if a heat pump had a perfect 4.0 COP all winter, gas would be ~15% cheaper. Electricity prices really need to come down before it will be viable for everyone.
  - doctorhandshake 1y ago
    Yeah. Sadly the trend does not seem to be heading that direction what with the current admin’s … policies and the whole … AI … thing.
  - kragen 1y ago
    Get solar.
    - crgwbr 1y ago
      I’ve tried. For it to be at all viable on my property, I’d need to cut down a bunch of trees. I’d rather keep the trees and pay someone else with solar panels.
      - kragen 1y ago
        That makes sense. Is that legal?
        kragen 1y ago
        I mean, in many countries, often either the government or a company closely allied to the government has been granted a legal monopoly on selling electrical energy, so buying electricity from other people is illegal.
  - etimberg 1y ago
    Not to mention, lots of places have time of use electricity pricing which makes it even worse. This is the problem with running my heatpump when its cold, some of the coldest times (right before dawn) coincide with peak time-of-use prices
- sokoloff 1y ago
  They have good heat output down to very low temperatures, but not good efficiency. The CoP is often around 2.0 at those very low temps, though (and of course the heat energy demanded is higher).
cycomanic 1y ago
I don't know what sort of heat pump systems are common in the US, but Sweden (and AFAIK Norway and Finland as well), are probably >%80 heat pump for single family homes (most apartments are community heating at least in the larger cities). So it's absolutely now problem to run a heat pump even if it is very cold outside, but if you want to improve efficiency in areas that are super cold you can drill into the ground for a heat sink (those are called Bergvärme in Sweden). Regarding cost, in most of the countries I've lived in a large fraction of the cost in the gas bill was the distribution cost. So once you switch to a heat pump, you also switch to electric cooking and even if heating with electricity would be significantly more expensive you would still win. Is that different in the US?
- DavidPeiffer 1y ago
  It varies significantly by locale. I've seen people post online about how it made little sense to keep just one gas appliance because of significant savings. I'm in Iowa, which typically heats on natural gas in urban areas. I have a natural gas central furnace and water heater. My clothes dryer is electric, and I have a 3 head heat pump which I use for comfort in a couple rooms. The house is an early 2000's standard builder-grade home. For September, $12.31 of my $27.01 gas bill was variable based on my consumption. In December, $84.82 out of my $99.65 total was consumption driven. I've run numbers on whether it'd make financial sense to go electric for heating, and the break even point is in the 30-40 degree vicinity. With temperatures 20 and under a healthy chunk of the year, unfortunately the added expense doesn't make financial sense.
yxhuvud 1y ago
It works just fine during winters if you do it properly and couple them with ducts that are a couple of hundred meters deep.

corbet 1y ago

My heat pump, in Colorado, kept the house warm at -18°F last winter. Without firing up the backup resistance heating strip. I think it works. (It is more expensive to operate than the natural-gas furnace was, though).

skywhopper 1y ago
Insulation matters as well and I’m guessing your Colorado house is far newer and better sealed than most New England homes.

doctorhandshake 1y ago

The notion that heat pumps don’t work at low temperatures hasn’t been true for years. I think you may be surprised to find that just about any heat pump you look at has good efficiency down to very low temperatures.

Loughla 1y ago
Define low temperatures. Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps.
- doctorhandshake 1y ago
  I’m not sure what yours is but it doesn’t sound appropriate to your application. Mitsubishi hyper heat is indicative of a contemporary inverter design - 100% efficiency to -5f: https://www.mitsubishicomfort.com/articles/mythbusters-heat-pumps-for-extreme-cold-climates https://www.mitsubishicomfort.com/articles/mythbusters-heat-...
  - sokoloff 1y ago
    100% efficiency is terrible for a heat pump. Electric resistance heat is 100% efficient.
    - doctorhandshake 1y ago
      I should have said 100% performance. COP is typically 3-4:1 with mitsu
      - sokoloff 1y ago
        Typical seasonal average? Sure. At -5°F? Hell no! At +5°F, they rate their own equipment to have a 2.0 CoP. https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10007%5CM_SUBMITTAL_MXZ-4C36NAHZ2-en.pdf https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.c...
        throw0101a 1y ago
        Here's a Trane/Mitsubishi unit that has a COP of (at least) 3 at -13F/-25C: * https://ashp.neep.org/#!/product/156605/7/25000/95/7500/0///0 https://ashp.neep.org/#!/product/156605/7/25000/95/7500/0///... An LG unit with 2.4 at -4F/-20C: * https://ashp.neep.org/#!/product/29688/7/25000/95/7500/0///0 https://ashp.neep.org/#!/product/29688/7/25000/95/7500/0///0 Searchable database of cold climate air source heat pumps (ccASHPs): * https://ashp.neep.org/#!/product_list/ https://ashp.neep.org/#!/product_list/
        sokoloff 1y ago
        Correct (and thanks for the link to that unit). Though it’s worth noting that that first 2 ton rated unit is putting out 0.5 tons (6k BTU/hr) at that temp and rating. That’s not going to be particularly helpful for a structure that needed 24k BTU/hr during warmer temps, meaning the owner of the unit is likely mixing in a lot of 1.0 BTUs to meet the heat loss at -13°F.
- crazygringo 1y ago
  I've got one about 8 years old, and it does just fine down to 0°F (it hasn't gotten colder than that here). It doesn't even have any kind of auxiliary heat. It's fine. The only difference when it's super-cold is that the air coming out of it isn't as warm, so the heating cycle stays on for a longer proportion of the time. But it keeps it 70°F inside no problem at all.
- tzs 1y ago
  That's one of the older style units. Starting in 2007 when Mitsubishi introduced their "Hyper-Heating Inverter" heat pumps, and continuing with Fujitsu and Daikin following with similar technology in the 2010-12 timeframe, and others a few years later, heat pumps got way better in the cold. Mitsubishi's maintain 200%+ efficiency down to -4℉ (-20℃) and 150% down to -22℉ (-30℃) [1]. Only a few towns in the continental US get below that, and even those aren't going to get cold enough long enough to make it worth it an an all electric home to switch to your emergency electrical resistance heating. Their capacity doesn't start dropping until you get down to 23℉ (-5℃), dropping to 76% at -13℉ (-25℃). [1] https://www.coolingpost.com/world-news/study-proves-heat-pump-efficiency-at-low-temperatures/ https://www.coolingpost.com/world-news/study-proves-heat-pum...
- throw0101a 1y ago
  > Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps. What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: * https://basc.pnnl.gov/images/iecc-climate-zone-map https://basc.pnnl.gov/images/iecc-climate-zone-map ASHRAE—an HVAC organization—has data on the coldest and hottest days for areas so that you can design things for the coldest or hottest 1% of the year (4 hottest/coldest days): * https://ashrae-meteo.info/v2.0/ https://ashrae-meteo.info/v2.0/ I think that if you have an older, leaky/ier, less-insulated house you may need to 'brute force' heating your (probably older) domicile. But if you have a <4 ACH@50 air tightness, and reasonable insulation levels, a good portion of the US population could make do with a heat pump. Mitsubishi publishes data were they have 100% heating capacity at -15C, which some models being 100% at -20C and -23C: * https://www.mitsubishielectric.ca/en/hvac/home-owners/zuba https://www.mitsubishielectric.ca/en/hvac/home-owners/zuba At -25C they have 80% capacity: * https://www.mitsair.com/wp-content/uploads/2024/10/MEM-202406-E_ZubaRebrandBroch_LR_FIN-1.pdf https://www.mitsair.com/wp-content/uploads/2024/10/MEM-20240...
  - whateveracct 1y ago
    > What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: A lot? e.g. Chicago gets it every year
    - throw0101c 1y ago
      >>> Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps. >> > What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen: > A lot? e.g. Chicago gets it every year [citation needed] Per historical weather data: https://ashrae-meteo.info/v2.0/index.php?lat=41.960&lng=-87.932&place=%27%27&wmo=725300 https://ashrae-meteo.info/v2.0/index.php?lat=41.960&lng=-87.... It is warmer than -16C/3F at Chicago (O'Hare) for 99% of the time (i.e., except for 4 days a year), and warmer than -18.7C/-2F for 99.6% of the time (2 days). ASHRAE are the folks that publish the heating/cooling standards that are used in building codes for estimate heating/cooling equipment capacities (Manual J) and selecting the right equipment (Manual S). Here's a PDF with a lot of locations in the US and CA (and other countries further down), and if you look under the "Heating DB" column, you'll find very few US locations that have -30F under the 99% (or even 99.6%) sub-columns: * https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/winter_summer_design_temps_us.pdf https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/... So unless you're in AK, MN, or ND, long runs of temperatures colder than -20F/-30C don't happen too often. Of course if you have a leaky house with little insulation, you're throwing money out the window/door, so the first consideration for a good ROI is better air sealing and insulation.
crgwbr 1y ago
That’s true, but still doesn’t always make heat pumps the most cost effective choice to operate. For example, last winter I paid an average of $0.24/kWh for electricity vs $0.05/kWh for natural gas. Even if a heat pump had a perfect 4.0 COP all winter, gas would be ~15% cheaper. Electricity prices really need to come down before it will be viable for everyone.
- doctorhandshake 1y ago
  Yeah. Sadly the trend does not seem to be heading that direction what with the current admin’s … policies and the whole … AI … thing.
- kragen 1y ago
  Get solar.
  - crgwbr 1y ago
    I’ve tried. For it to be at all viable on my property, I’d need to cut down a bunch of trees. I’d rather keep the trees and pay someone else with solar panels.
    - kragen 1y ago
      That makes sense. Is that legal?
      - kragen 1y ago
        I mean, in many countries, often either the government or a company closely allied to the government has been granted a legal monopoly on selling electrical energy, so buying electricity from other people is illegal.
- etimberg 1y ago
  Not to mention, lots of places have time of use electricity pricing which makes it even worse. This is the problem with running my heatpump when its cold, some of the coldest times (right before dawn) coincide with peak time-of-use prices
sokoloff 1y ago
They have good heat output down to very low temperatures, but not good efficiency. The CoP is often around 2.0 at those very low temps, though (and of course the heat energy demanded is higher).

cycomanic 1y ago

I don't know what sort of heat pump systems are common in the US, but Sweden (and AFAIK Norway and Finland as well), are probably >%80 heat pump for single family homes (most apartments are community heating at least in the larger cities). So it's absolutely now problem to run a heat pump even if it is very cold outside, but if you want to improve efficiency in areas that are super cold you can drill into the ground for a heat sink (those are called Bergvärme in Sweden). Regarding cost, in most of the countries I've lived in a large fraction of the cost in the gas bill was the distribution cost. So once you switch to a heat pump, you also switch to electric cooking and even if heating with electricity would be significantly more expensive you would still win. Is that different in the US?

DavidPeiffer 1y ago
It varies significantly by locale. I've seen people post online about how it made little sense to keep just one gas appliance because of significant savings. I'm in Iowa, which typically heats on natural gas in urban areas. I have a natural gas central furnace and water heater. My clothes dryer is electric, and I have a 3 head heat pump which I use for comfort in a couple rooms. The house is an early 2000's standard builder-grade home. For September, $12.31 of my $27.01 gas bill was variable based on my consumption. In December, $84.82 out of my $99.65 total was consumption driven. I've run numbers on whether it'd make financial sense to go electric for heating, and the break even point is in the 30-40 degree vicinity. With temperatures 20 and under a healthy chunk of the year, unfortunately the added expense doesn't make financial sense.

yxhuvud 1y ago

It works just fine during winters if you do it properly and couple them with ducts that are a couple of hundred meters deep.