It's semi-true even with modern systems and shouldn't be outright dismissed as "nonsense".

A normal person is scared of the prospect of losing heating when it's most needed. -15F accounts for many places in the US, but many others, not so much. Even New Jersey, which we don't think of as the frigid North, can theoretically drop below that number, and nobody wants "almost always" when it comes to life-giving heat in the coldest winter.

I live north of New Jersey by 300 miles and have only used a heat pump for winter heating for 10 years

no, this is complete nonsense and should be dismissed as such.

People being "scared" is how north america ended up with vehicles the size of tanks. The vast majority of cold climate heat pumps work down to - 20 C in most cases and down to -30 with better models.

What’s the COP at -15F? It’s probably close to 1, which means you’re paying for resistive heat which happens to be the most expensive possible way to heat something up.

A Mitsubishi Hyper-heat MXZ-4C36NAHZ for instance has a COP of 2.12 at -13F outdoor temp and 70F indoor temp.

That’s actually a lot better than I expected, thanks!

Yeah most places aren't consistently -15F, not going to be a dealbreaker for a week.

If you live in Minnesota stick with gas, we'll be ok. The majority of the population will never hit -15F.

That’s the thing, I do live in Minnesota. Most of the lower 48 can benefit from heat pumps but unfortunately in Minnesota (and the upper Midwest that isn’t directly adjacent to a Great Lake which moderates the temperature) you either need resistive heating on the heat pump condenser coil to prevent icing and/or a backup natural gas furnace/boiler for the few weeks it stays below zero for days on end.

For the west coast or areas south of 40 degrees north and east of the Rockies in the US and most of Canada where people actually live (southern Ontario is warm to due Lake Ontario), heat pumps are probably more efficient and cheaper overall.

Minnesota is definitely an outlier with regards to heat pump vs natural gas heating.

Institutional type buildings in Minnesota are switching over to condensing boilers, which are amazingly efficient, well over 90% of the heat is used, and they’re a fraction of the size of the old tube style iron boilers. I’m personally involved in multiple commercial boiler replacements a year.

I am seeing more geothermal installations in MN as well, that works better than air source heat pumps in Minnesota due to the source/sink being a stable 50F instead of having a 80-90F delta like an air source heat pump when it’s -20F outside

One more thing, both Minneapolis and St Paul have district heating and cooling systems in their downtown areas. The University of Minnesota also operates district chilled water and hot water plants in both their Mpls and St Paul campuses.

Just checked the spec of mine at -10degC. It's a bit over 3.

That’s +15F, what’s the COP at -26C?

Whoops, my bad when doing the transformation. It won't work that low, only down to 20degC and at that point it probably approaches 1. Lucky me, the temps never dropped to under 19degC in the last 20 years in my area. So I'm probably going to be fine.