For our companion unit we put in a heatpump unit. We had to meat full title 24 energy codes and this was the best way. Plus, since my in-laws are in their 80’s, they might use the AC for part of the summer. (And when the in-laws aren’t there, my 70-something year old aunt comes out to spend part of the summer.)
The climate is mild enough here (at least if you’re semi-coastal) that a heat pump works well for the moderate heating/cooling.
I have a friend in PA that’s home came with a heat pump – in the winter his bills skyrocketed because the heater ended up being resistive heating when the temps dropped into the 30’s.
