We only used the RV furnace last winter when temp got to zero, and mainly to heat basement & underbelly... RV furnace is grossly inefficient having too much heat being exhaust. Our main heater is an electric oil filled radiator style heater (1500 watt)... warms the complete downstairs even into the low 20s outside. Will maintain interior 70-72 degrees. Below 20, we supplement with the fireplace heater at night. We use a ultra quiet heater for the bath/bedroom. With sustained temps below freezing we have a circular heater in the basement (basement is empty) set to lowest setting. It generally maintains 45-50 degrees in the basement to protect water lines. This also helps heat the underbelly which is open to the basement 40 degrees to protect holding tanks and water lines. Helps keep the floor a bit warmer too. Several years ago we did a winter heating study. Using RV furnace for all the heating plus normal electric usage, we had a $140 monthly bill. Using electric for everything the bill was $95. The rv furnace wasted $45 via the losses at the exhaust. RV furnaces are also noisy and create hot & cold spots in the RV, turning on & off. Electric maintains constant heat and the ceiling fan on low keeps the heat uniform throughout the rv. Our rv also has an extreme artic package which helps greatly. Thermal curtains at night time also help. Our first rv, 24 ft Class C, had almost no insulation and was a bear to keep warm & cool.
Additional winter tips: insulated water supply hose of best strip... raise electric & water lines off the ground... We also use a trickle drip hose that connects inside the RV and drains outside without going through the holding tanks (keeps the water supply line from freezing).
