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>These days, a heat pump is more than capable of both heating and cooling even in the depths of a New England winter Are you talking about air source or ground

>These days, a heat pump is more than capable of both heating and cooling even in the depths of a New England winter Are you talking about air source or ground source? And by "the depths of a New England winter" do you mean temperatures below 50 F? I lived in an apartment for a while that had some sort of heat pump, but there was a switch for "emergency" (i.e. resistive) heat that was necessary for any warmth in the winter.

stan_rogers 6y ago
It would be ground source, and a day of 50°F would feel like shorts and sandals weather that time of the year.
- perl4ever 6y ago
  You don't have to tell me. I was looking for sources of misunderstanding. In a multifamily structure, at 50 F, in my experience, heat through shared walls probably keeps you reasonably warm without any heat of your own.
fyfy18 6y ago
Modern air source heat pumps can be effective down to -25C (-13F) in heat pump mode, and will automatically switch to resistance heating if needed. I'm building a house where it can get to -35C at times (but usually above -20C in winter) and we will have an air source heat pump for hot water, heating and cooling [0]. Combined with good insulation and 10kW of solar on the roof, we should generate more electricity than we use over the year, and no need to burn any fossil fuels. My wife has insisted we have a wood burning stove for atmosphere, so that will function as a backup heat source if needed, but most likely it will generate too much heat to be used regularly. [0] https://www.daikin.eu/en_us/product-group/air-to-water-heat-pump-low-temperature/daikin_altherma_3_r.html https://www.daikin.eu/en_us/product-group/air-to-water-heat-...
- perl4ever 6y ago
  I tend to take a dim view of the phrase "can be" because it's so weak. It's logically equivalent to "may not be" and is entirely consistent with "essentially never is". But sure, the heat pump in your future home may well be much better than whatever they were doing decades ago. I don't know if my apartment used ground heat, but I doubt it.
  - fyfy18 6y ago
    I meant "can be" in that if you buy one rated for those temperatures it will reach that, but not all heat pumps are rated for that.
MertsA 6y ago
Your heat pump had something wrong with it. Quite possibly it wasn't going into defrost mode or wasn't able to actually finish defrosting by the end of a cycle. The way that's intended to work is that after running for a bit when the ice starts blocking air flow and insulating the coils on the outdoor unit it'll switch to cooling mode and turn on resistive heating. That quickly thaws out the coils and then it switches back to heating and turns off the resistive heating inside. I find it odd that you even had to manually turn on emergency heat to get any heating out of it. Normally if the thermostat is too far below the setpoint it'll automatically start using resistive heating as well (most thermostats will indicate "aux heat" when that happens). Maybe your thermostat didn't? Or it did and the reversing valve was stuck so it was just stuck in cool mode 100% of the time.

stan_rogers 6y ago

It would be ground source, and a day of 50°F would feel like shorts and sandals weather that time of the year.

perl4ever 6y ago
You don't have to tell me. I was looking for sources of misunderstanding. In a multifamily structure, at 50 F, in my experience, heat through shared walls probably keeps you reasonably warm without any heat of your own.

fyfy18 6y ago

Modern air source heat pumps can be effective down to -25C (-13F) in heat pump mode, and will automatically switch to resistance heating if needed. I'm building a house where it can get to -35C at times (but usually above -20C in winter) and we will have an air source heat pump for hot water, heating and cooling [0]. Combined with good insulation and 10kW of solar on the roof, we should generate more electricity than we use over the year, and no need to burn any fossil fuels. My wife has insisted we have a wood burning stove for atmosphere, so that will function as a backup heat source if needed, but most likely it will generate too much heat to be used regularly. [0] https://www.daikin.eu/en_us/product-group/air-to-water-heat-pump-low-temperature/daikin_altherma_3_r.html https://www.daikin.eu/en_us/product-group/air-to-water-heat-...

perl4ever 6y ago
I tend to take a dim view of the phrase "can be" because it's so weak. It's logically equivalent to "may not be" and is entirely consistent with "essentially never is". But sure, the heat pump in your future home may well be much better than whatever they were doing decades ago. I don't know if my apartment used ground heat, but I doubt it.
- fyfy18 6y ago
  I meant "can be" in that if you buy one rated for those temperatures it will reach that, but not all heat pumps are rated for that.

MertsA 6y ago

Your heat pump had something wrong with it. Quite possibly it wasn't going into defrost mode or wasn't able to actually finish defrosting by the end of a cycle. The way that's intended to work is that after running for a bit when the ice starts blocking air flow and insulating the coils on the outdoor unit it'll switch to cooling mode and turn on resistive heating. That quickly thaws out the coils and then it switches back to heating and turns off the resistive heating inside. I find it odd that you even had to manually turn on emergency heat to get any heating out of it. Normally if the thermostat is too far below the setpoint it'll automatically start using resistive heating as well (most thermostats will indicate "aux heat" when that happens). Maybe your thermostat didn't? Or it did and the reversing valve was stuck so it was just stuck in cool mode 100% of the time.