We have in floor radiant heat (water ) with 1 1/2 " foam insulation under floor . When on the road with engine heat 180* the whole coach is as warm as we want . When parked or on the pole I have a 2 gal. elect water heater that will heat the coach until about 25 * f colder then that I use the proheat .I installed a valve on the input to the engine two shut off the eng. heat. So that only to heat the floor . The proheat will keep the coach as warm as we want and dose not cycle on very much . The coldest temp we have been in was 5 * Fahrenheit ( to cold to be camping in ) . dave
Problem solved just move to AZ where there is no humidity in the air to remove....