This is quantified by "heating degree days" and I don't think your intuition is correct here. https://upload.wikimedia.org/wikipedia/commons/d/da/United_States

This is quantified by "heating degree days" and I don't think your intuition is correct here. https://upload.wikimedia.org/wikipedia/commons/d/da/United_States_Heating_Degree_Day_map%2C_1961-1990.jpg https://upload.wikimedia.org/wikipedia/commons/d/da/United_S... The difference between "Can use a heat pump" and "can't" is only maybe 10º or 15º. The coldest places are only ~20% colder than much more populated areas with millions of more residents. Metro Boston has around 5 million people -- that's more than 3x as many as who live in North Dakota and South Dakota combined. Their climate is cold and they get around 6,000 HDD every winter compared to the frigid upper plains who average something like 8,000 or 8,500. So 1.3x more heat requirement per person but spread out across 1/3 as many people. Not to mention all of e.g. Chicago, Denver, Des Moines, Cleveland, Detroit, New York, the rest of New England, etc. etc. where heat pumps do just fine.