6 ms·

This problem isn't unique to heat pumps though. Obviously resistive electric has the same problem, but also gas furnaces are useless if you also need the fan ru

This problem isn't unique to heat pumps though. Obviously resistive electric has the same problem, but also gas furnaces are useless if you also need the fan running to distribute air through ductwork.

superkuh 2y ago
Gas furnace and resistive electric work everywhere when they work. This isn't true of heat pumps. They only work in most climates. But it'd be tough using a heat pump around Minneapolis or Moscow when it's -20F for a week. The non-universality of heat pumps is a speed bump in path to use.
- gnabgib 2y ago
  There are multiple types of heat pumps. Ground-source heat pumps will work to -30c and beyond[0]. If you buy a cold climate air-source heat pump it will also work to -30c (while a conventional model taps out around -10c). They also provide cooling in summer. [0]: https://www.cbc.ca/news/science/heat-pump-faq-1.6824634 https://www.cbc.ca/news/science/heat-pump-faq-1.6824634
  - superkuh 2y ago
    I hope things have changed. 10 years ago when I rented a house with a ground source heat pump each winter was terrible. The frost depth here defined by building code is 60". I imagine that system had been burried much too shallow to be effective. Which brings me to my point: the colder a region is the further down in the ground you have to dig the more costly that excavation rapidly becomes. Ground-source heat pumps are not a competitive solution for cold places in terms of up-front cost.
  - jebarker 2y ago
    Yep. We heat our house through Colorado winters (pretty cold, but not really cold) with just a high efficiency heat pump and resistive backup in the air handler. The resistive is rarely needed. This is beside the point though which was that even non-electric heating systems often require electricity to function.
  - bryanlarsen 2y ago
    Another choice for cold climates is a cascading heat pump: 2 or 3 heat pumps in series, each with a different working fluid.
fwungy 2y ago
Fan is a small load. You could run that from a generator. You wouldn't want to run a heat pump from a generator.
- erik_seaberg 2y ago
  Wouldn't the heat pump and generator do better than burning the same fuel in a gas furnace?

superkuh 2y ago

Gas furnace and resistive electric work everywhere when they work. This isn't true of heat pumps. They only work in most climates. But it'd be tough using a heat pump around Minneapolis or Moscow when it's -20F for a week. The non-universality of heat pumps is a speed bump in path to use.

gnabgib 2y ago
There are multiple types of heat pumps. Ground-source heat pumps will work to -30c and beyond[0]. If you buy a cold climate air-source heat pump it will also work to -30c (while a conventional model taps out around -10c). They also provide cooling in summer. [0]: https://www.cbc.ca/news/science/heat-pump-faq-1.6824634 https://www.cbc.ca/news/science/heat-pump-faq-1.6824634
- superkuh 2y ago
  I hope things have changed. 10 years ago when I rented a house with a ground source heat pump each winter was terrible. The frost depth here defined by building code is 60". I imagine that system had been burried much too shallow to be effective. Which brings me to my point: the colder a region is the further down in the ground you have to dig the more costly that excavation rapidly becomes. Ground-source heat pumps are not a competitive solution for cold places in terms of up-front cost.
- jebarker 2y ago
  Yep. We heat our house through Colorado winters (pretty cold, but not really cold) with just a high efficiency heat pump and resistive backup in the air handler. The resistive is rarely needed. This is beside the point though which was that even non-electric heating systems often require electricity to function.
- bryanlarsen 2y ago
  Another choice for cold climates is a cascading heat pump: 2 or 3 heat pumps in series, each with a different working fluid.

fwungy 2y ago

Fan is a small load. You could run that from a generator. You wouldn't want to run a heat pump from a generator.

erik_seaberg 2y ago
Wouldn't the heat pump and generator do better than burning the same fuel in a gas furnace?