I’m always fascinated by how heat pumps (or reverse cycle units for Australians) are not the defacto standard in other countries and somehow come up for debate in the US. I remember watching one of the many TechnologyConnections videos on the subject and was wondering although interesting, what is with this focus on heat pumps being better than XYZ? Is the resistance to change really that great?
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 I also think it’s been a hot minute since I’ve seen household evap cooling, which I find has slowly been replaced by reverse cycle units given the climate has changed for us in VIC that the humidity increase over the years tends to make the evap units far less effective.
The US economy is basically one big pyramid scheme that has been divided amongst several cartels. If you try to exit or interrupt the momentum, they get very mad and pull the levers on the various influence channels they also own (industry, media, government, etc.). Individual consumers are then frightened, overwhelmed, or priced out of change, assuming they’re even aware of it.
The newer air source models have good performance well below freezing. Older models didn't really.
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.
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):
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):
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).
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.