AimlessWanderLust wrote:
Condensation will build up fast if you have all the windows and vents closed. We open the roof vent above the bed a small crack and open a vent/window near to the floor a small crack. This keeps air circulating through the camper, and eliminates condensation. Yes, heat is lost through the roof vent, but it's not significant enough to make the furnace cycle much more. I'd also rather have to run a heater longer than deal with mold/mildew from condensation!
There's the answer. Good Ventilation = No rain forest. So the heat has to run a bit more, better than being woke up by dripping ceilings of having flooding on the bunk beds or dinnette table.