From Rockets to Heat Pumps
heatpumped.org
heatpumped.org
Being Australian, at least in Victoria, I don’t know of many houses that have gas heating. I also think it’s been a hot minute since I’ve seen household evap cooling, which I find has slowly been replaced by reverse cycle units given the climate has changed for us in VIC that the humidity increase over the years tends to make the evap units far less effective.
Don't heat pumps suck when it gets Actually Cold in the winter? Let's say -40F to 0F (-40C to -18C)?
If so, that would be why. A lot of places here get quite cold.
https://www.theguardian.com/environment/2023/nov/23/norway-h...
Heat pumps in Alaska:
* https://www.adn.com/business-economy/energy/2024/09/01/energ...
However, before spending money on new mechanical units, it's usually better to improve insulation and air tightness first: there's no sense heating (or cooling) and then have the conditioned air leak in/out of the house.
Further, there are hybrid / dual-fuel systems: you operate the heat pump down to X ˚C and at that point switch over to burning something.
All that said, heat pumps can be used up to at least IECC Zone 5, and with a decently insulated house in Zone 6 (you probably need pretty good insulation to get into Z7):
* https://basc.pnnl.gov/images/iecc-climate-zone-map
* https://basc.pnnl.gov/resource-guides/cold-climate-heat-pump...
* https://heatpumpdata.energy.gov/data/studies/nrel-field-vali...
There are certification for working down to -15C/5F:
* https://neep.org/heating-electrification/ccashp-specificatio...
And while there are areas of the world where it gets that cold, how many people live there (relatively speaking)? I would hazard to guess that large portions of the human population (even in the US) do not live in areas that get much worse (on average) than -20C/-5F, and so large portions of the population are eligible for HP use. (And I'm saying this as a Canadian.)
When deciding on what kind of heating/mechanical system to get, many building codes dictate that you have to design around how much energy you house will need for you area. The historical data is readily available (left-click to scroll, right-click to choose):
* https://ashrae-meteo.info/v3.0/
For heating see "Heating DB 99%" (which means that historically the temperature has been warmer than the listed value 99% of the time, i.e., except for ~4 days out of any year (on average)); for cooling, "Cooling DB 1%" (historical temps have been lower except for 1% of the time).
You actually don't want insane insulation. Alaska is wet, and if you trap condensation and add heat for warmth, you get mold.
Yes, you do want high insulation, and also good air tightness.
* https://buildingscience.com/documents/insights/bsi-031-build...
* https://buildingscience.com/documents/insights/bsi-001-the-p...
* https://cchrc.org/wp-content/uploads/media/arctic_wall2013.p...
You want a very good building envelope and you control inside conditions through mechanical means. You control condensation dehumidifiers.
Costs also matter. Some relatives that are on the fairly expensive rural electric operator around here installed a ground source heat pump, at pretty high up front cost. They wouldn't have bothered if they had a natural gas hookup.