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Are you saying heat pumps won’t work in cold climates? That hasn’t been true in some time. https://www.greenbuildingadvisor.com/article/heat-pumps-for-cold-clim

Are you saying heat pumps won’t work in cold climates? That hasn’t been true in some time. https://www.greenbuildingadvisor.com/article/heat-pumps-for-cold-climates https://www.greenbuildingadvisor.com/article/heat-pumps-for-...

bluGill 3y ago
Heat pumps work down to -25C. Cold climates get colder than that. Sure most cold climates are typically above that, but it only takes one night every 10 years to hit those temperatures and a heat pump alone does not work. You need a backup. Of cousre once we have a backup we can ask if it is cost effect - heat pumps get less efficient as temperatures go down - when you need the most heat, so it may be most cost effective to install a heat pump that doesn't even work to that cold (perhaps it does but is under sized?) and just use backup heat when it is cold.
- wtallis 3y ago
  One night where the outside temperature gets below -25C is not a serious problem. If you had the heat pump keeping your house at a comfortable temperature the day before, you aren't going to die of hypothermia or have pipes freeze overnight. You'll just wake up to a house that's chilly inside and takes most of the day to get back up to where you want it. Sustained cold spells are where you need an alternative heat source.
  - google234123 3y ago
    Also electric heaters are dirt cheap - get a bunch 20$ ones
    - wlonkly 3y ago
      Or conveniently mount one inside your air handler!
- doctorhandshake 3y ago
  What you’re talking about is factored in to system design - it’s called the 1% design temperature. https://www.greenbuildingadvisor.com/article/design-temperature-vs-degree-days https://www.greenbuildingadvisor.com/article/design-temperat... As CP says, you design your system for the conditions 99% of the time, because designing for that last 1% leads to a terrible cost benefit calculation. Same reason you don’t daily drive an armored personnel carrier with a 300-gallon gas tank.
- micromacrofoot 3y ago
  I live in one of these areas and I just use a couple electric space heaters a few days a year - my mini splits are still great otherwise.
- darkr 3y ago
  I presume you’re talking about air source heat pumps here. Some will go down that far, but it’s not common. If installed in a location where winters will routinely see temperatures below -10/15 degrees C, it’s going to be far more efficient to do a ground source heat pump, ideally with a deep bore hole where you can get a heat source that is continually 10-20 degrees C

bluGill 3y ago

Heat pumps work down to -25C. Cold climates get colder than that. Sure most cold climates are typically above that, but it only takes one night every 10 years to hit those temperatures and a heat pump alone does not work. You need a backup. Of cousre once we have a backup we can ask if it is cost effect - heat pumps get less efficient as temperatures go down - when you need the most heat, so it may be most cost effective to install a heat pump that doesn't even work to that cold (perhaps it does but is under sized?) and just use backup heat when it is cold.

wtallis 3y ago
One night where the outside temperature gets below -25C is not a serious problem. If you had the heat pump keeping your house at a comfortable temperature the day before, you aren't going to die of hypothermia or have pipes freeze overnight. You'll just wake up to a house that's chilly inside and takes most of the day to get back up to where you want it. Sustained cold spells are where you need an alternative heat source.
- google234123 3y ago
  Also electric heaters are dirt cheap - get a bunch 20$ ones
  - wlonkly 3y ago
    Or conveniently mount one inside your air handler!
doctorhandshake 3y ago
What you’re talking about is factored in to system design - it’s called the 1% design temperature. https://www.greenbuildingadvisor.com/article/design-temperature-vs-degree-days https://www.greenbuildingadvisor.com/article/design-temperat... As CP says, you design your system for the conditions 99% of the time, because designing for that last 1% leads to a terrible cost benefit calculation. Same reason you don’t daily drive an armored personnel carrier with a 300-gallon gas tank.
micromacrofoot 3y ago
I live in one of these areas and I just use a couple electric space heaters a few days a year - my mini splits are still great otherwise.
darkr 3y ago
I presume you’re talking about air source heat pumps here. Some will go down that far, but it’s not common. If installed in a location where winters will routinely see temperatures below -10/15 degrees C, it’s going to be far more efficient to do a ground source heat pump, ideally with a deep bore hole where you can get a heat source that is continually 10-20 degrees C