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I've been wondering about this! I keep hearing that air-source heat pumps aren't great in pretty cold areas. Do you have any links or references on this? I live

by Glench 6y ago

I've been wondering about this! I keep hearing that air-source heat pumps aren't great in pretty cold areas. Do you have any links or references on this? I live in the Northeast US and wanted to see what the options were and what people's experiences have been.

doikor 6y ago
Basically the Coefficient of performance (COP or SCOP for seasonal version) just keeps going down with the temperature (under 1 means resistance heating is better) https://en.wikipedia.org/wiki/Coefficient_of_performance https://en.wikipedia.org/wiki/Coefficient_of_performance Models made for cold climate work to around -30c. Wikipedia has okish writeup about their functionality in cold climates https://en.wikipedia.org/wiki/Air_source_heat_pump#In_cold_climates https://en.wikipedia.org/wiki/Air_source_heat_pump#In_cold_c... Don't really have any good sources in English for this (most reading I have done on this is in Finnish) For example here are some excerpts from a report done by VTT (the Finnish governments research center) https://www.scanoffice.fi/vttn-testiraportit-ilmalampopumppuvertailu/ https://www.scanoffice.fi/vttn-testiraportit-ilmalampopumppu... If you scroll down you can find some pics "lämpökerroin" is COP and "ulkoilman lämpötila" is outside temperature. From that you can see that the combo of Mitsubishi Electric MSZ-LN25VGW + MUZ-LN25VGHZ still holds a COP of 2 at -30c. On the models not made for such climate/cheap ones you can see it drop to 1 (or below)
- Glench 6y ago
  Ooh awesome thanks for the references!
bluGill 6y ago
My previous house has an air source heat pump. There was a thermometer outside and the furnace automatically switched from the heat pump to gas heat when the temperature was below 14f. (some heat pumps work to colder temperatures). I saved a lot of money over the cost of propane (which is more expensive than nat gas), and didn't really notice any problems.
kwhitefoot 6y ago
Every third house has an air source heat pump where I live in Norway about 40 km south of Oslo. My next door neighbour has two. The produce more heat than the input electricity until the temperature falls to about -25 C.

by Glench 6y ago

doikor 6y ago

Basically the Coefficient of performance (COP or SCOP for seasonal version) just keeps going down with the temperature (under 1 means resistance heating is better) https://en.wikipedia.org/wiki/Coefficient_of_performance https://en.wikipedia.org/wiki/Coefficient_of_performance Models made for cold climate work to around -30c. Wikipedia has okish writeup about their functionality in cold climates https://en.wikipedia.org/wiki/Air_source_heat_pump#In_cold_climates https://en.wikipedia.org/wiki/Air_source_heat_pump#In_cold_c... Don't really have any good sources in English for this (most reading I have done on this is in Finnish) For example here are some excerpts from a report done by VTT (the Finnish governments research center) https://www.scanoffice.fi/vttn-testiraportit-ilmalampopumppuvertailu/ https://www.scanoffice.fi/vttn-testiraportit-ilmalampopumppu... If you scroll down you can find some pics "lämpökerroin" is COP and "ulkoilman lämpötila" is outside temperature. From that you can see that the combo of Mitsubishi Electric MSZ-LN25VGW + MUZ-LN25VGHZ still holds a COP of 2 at -30c. On the models not made for such climate/cheap ones you can see it drop to 1 (or below)

Glench 6y ago
Ooh awesome thanks for the references!

bluGill 6y ago

My previous house has an air source heat pump. There was a thermometer outside and the furnace automatically switched from the heat pump to gas heat when the temperature was below 14f. (some heat pumps work to colder temperatures). I saved a lot of money over the cost of propane (which is more expensive than nat gas), and didn't really notice any problems.

kwhitefoot 6y ago

Every third house has an air source heat pump where I live in Norway about 40 km south of Oslo. My next door neighbour has two. The produce more heat than the input electricity until the temperature falls to about -25 C.