There are definitely still places in the U.S. where air-source heat pumps aren't economical. That said, two big things for most folks to keep in mind:
1. Air-source heat pumps are getting better and better, quickly, so that answer is changing
2. 93% of US homeowners would save money with air-source heat pumps vs. their existing equipment, and only 3% of homes would see an annual utility bill increase above $70. (these from backtesting the national sample of homes from the EIA's RECS survey)
A lot of people think "really really cold" means it hits zero a few times each winter. They don't know what living in Fairbanks is like :), and chances are that heat pumps can keep up with their local weather.
>A lot of people think "really really cold" means it hits zero a few times each winter
See this seems to me an illustration of something being hinky about the discussion.
"Hits zero a few times each winter" quite possibly is an accurate description of the climate where I live. I believe only one month had a below zero low recorded last winter.
But representing my climate with that particular factoid would gloss over that lows around freezing down to subzero are typical for like six months of the year, and the other six months, you don't need heat in the first place.
A lot of people in the CONUS really do live where winter is pretty harsh, not just North Dakota or something.
The important thing for saving on energy bills, which I don't ever see brought up in any online discussion about heat pumps, is how bimodal the climate is, not how extreme the winter lows are.
I can't say there is nowhere in the world where the temperature graaaaaaadually ramps up and down all year. But all I see is people taking for granted that's how it works and thus heat pumps spend a large amount of time in the optimal range.
1. Air-source heat pumps are getting better and better, quickly, so that answer is changing
2. 93% of US homeowners would save money with air-source heat pumps vs. their existing equipment, and only 3% of homes would see an annual utility bill increase above $70. (these from backtesting the national sample of homes from the EIA's RECS survey)
A lot of people think "really really cold" means it hits zero a few times each winter. They don't know what living in Fairbanks is like :), and chances are that heat pumps can keep up with their local weather.