Originally Posted by logistix
...Maybe this winter I will replace it with a heater if my Dometic Duotherm in the front ceiling of the bus doesn't perform well enough....
If it's a heat pump, then you may well be supplementing it with a heater. Heat pumps don't do very well below 40F. You may have a heat strip on it. The heat strip is "supposed" to heat well enough. But they do suck a bit of power. Not a problem if the electric is included with your site rent.