I'm in a similar zone and replaced (delivered) propane with a ground source heat pump 2 years ago. Constant temperature indoors (3C warmer in summer than winter

I'm in a similar zone and replaced (delivered) propane with a ground source heat pump 2 years ago. Constant temperature indoors (3C warmer in summer than winter) with plenty of AC capacity to spare. Breakeven is about 5 or 6 years.