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Heat Pumps Take on Cold Climates

spectrum.ieee.org

1–10 of 83 posts

Re: Heat Pumps Take on Cold Climates

#2
> But heat pump manufacturers say they now have the technology to heat homes just as efficiently in bitter cold as they do in milder winter temperatures.

This claim defies thermodynamics (and I expect better from IEEE).

Heat pumps are bound to be less efficient as the spread between inside and outside temperature grows. (They might be just as effective or they might be just as efficient as current heat pump tech, but they will not be as efficient at -20°C outside air temp as they are at +10°C.)

Re: Heat Pumps Take on Cold Climates

#3
Is there a way to get your house (currently with hydronic gas heat) retrofitted for heat pumps that doesn’t result in either a ton of demo or ugly lines all over the exterior? I tried to switch over last year only to find the savings were not that great in my climate, and that it would have an unacceptable aesthetic cost.

Re: Heat Pumps Take on Cold Climates

#4
post #2

> But heat pump manufacturers say they now have the technology to heat homes just as efficiently in bitter cold as they do in milder winter temperatures. This claim defies thermodynamics (and I expect better from IEEE). Heat pumps are bound to be less efficient as the spread between inside and outside temperature grows. (They might be just as effective or they might be just as efficient as current heat pump tech , bu…

Are they perhaps referring to geothermal heat pumps?

Re: Heat Pumps Take on Cold Climates

#6
post #3

Is there a way to get your house (currently with hydronic gas heat) retrofitted for heat pumps that doesn’t result in either a ton of demo or ugly lines all over the exterior? I tried to switch over last year only to find the savings were not that great in my climate, and that it would have an unacceptable aesthetic cost.

Mine has one pipe going into the basement, and the mains power connection. What sorts of ugly lines are you referring to?

Re: Heat Pumps Take on Cold Climates

#7
post #3

Is there a way to get your house (currently with hydronic gas heat) retrofitted for heat pumps that doesn’t result in either a ton of demo or ugly lines all over the exterior? I tried to switch over last year only to find the savings were not that great in my climate, and that it would have an unacceptable aesthetic cost.

Air to water heat pumps exist that can efficiently supply flow/LWT* of 135°F, so if you can turn down your existing boiler to 135°F flow and maintain temperature in the house, you can retrofit to an A2W heat pump, which does not result in your home being festooned with linesets and covers running around the outside like plastic termite tunnels.

I also tried to switch in 2022 and found that it would literally never pay off due to the dramatically higher upfront project cost, and so a combi gas boiler now hangs on my basement wall.

* - LWT = "leaving water temp" aka "supply" aka "flow" depending on where you are in the world

Re: Heat Pumps Take on Cold Climates

#9
post #6
post #3

Is there a way to get your house (currently with hydronic gas heat) retrofitted for heat pumps that doesn’t result in either a ton of demo or ugly lines all over the exterior? I tried to switch over last year only to find the savings were not that great in my climate, and that it would have an unacceptable aesthetic cost.

Mine has one pipe going into the basement, and the mains power connection. What sorts of ugly lines are you referring to?

I think probably the ugly lineset covers characteristic of lowest possible budget (and therefore overwhelmingly most common) installation of air-to-air heat pumps.

Re: Heat Pumps Take on Cold Climates

#10
post #3

Is there a way to get your house (currently with hydronic gas heat) retrofitted for heat pumps that doesn’t result in either a ton of demo or ugly lines all over the exterior? I tried to switch over last year only to find the savings were not that great in my climate, and that it would have an unacceptable aesthetic cost.

No, I think you got it. You either have a lot of work to install ductwork or you're going to be doing lots of mini splits with ugly lines all over the exterior.
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