"AC in reverse" I'm assuming means a heat pump, which is very common in the US except for the parts that get really cold like the Northeast and Midwest. They ar

"AC in reverse" I'm assuming means a heat pump, which is very common in the US except for the parts that get really cold like the Northeast and Midwest. They are very efficient down to a bit below freezing, but will result in higher electricity usage since you are using electricity instead of a different fuel.