[JandC]

It may depend on size or brand of heat pump or size or brand of air conditioner. Our SOB MH has 3 ceiling airs with heat pumps. This morning in N. Ft. Myers it was around 37 degrees and they worked great! Brought the inside of the coach up to 70 degrees in about 5 minutes. On our thermostat we can only select "air" or "HP".

So like others have indicated, if you scroll through the "mode" options on your thermostat and it doesn't say "HP" or "Heat-P" or something similar then your airs probably don't have it.