Why does anyone make A/C’s rather than just make Heat Pumps that run in both directions? Is there a cost difference?
In really cold climates (e.g. Minneapolis, Montreal) heat pumps often also need a supplemental furnace or fireplace because the heat differential inside vs. outside exceeds what the pump can handle. Depending on your fuel source, you still come out ahead, but not as much.
I should note that I'm not an expert by any means; my brother in law works in this field and he gave me a crash course a couple weeks ago. So I probably feel like I know it better than I actually do.