We had a DuoTherm heat pump for 12 years, and it was a real plus to the RV. Last year it finally went out (it runs a lot as we use our trailer as a guest room so everything remains hooked up). I replaced it with a new DuoTherm heat pump. The DuoTherm comes with a digital control that allows the heat pump to work to around thirty degrees, and if the outside temp continues to fall, it automatically switches over to the propane furnace. It saves an enormous amount of propane during the winter, because we have a lot of 30 to 50 degree days and nights. It's louder than the furnace, but it's the same sound level as when it's in AC mode in the summer. I guess I'd say that if you have really hard winters it won't help a lot except in spring and fall. But if you have moderate temps it is wonderful. I would not want a fifth wheel without one.