When it's cold out, keep your shades down, put something in the vent/fan openings as warm air goes thru those little plastic covers easily. We have also noticed that floor is cold and if sitting with your feet down, makes you feel colder. Put an extra layer on the floor where you sit. You will feel warmer. We also use electric heaters to supplement the propane furnace, but we do use the furnace to make sure our water stays good. Do NOT leave your grey tank valve open as you will end up with an ice chunk in your hose. Let your holding tanks fill and them empty, the black first, then the grey to rinse the hose. You can also put bubble wrap on the inside of the windows to help insulate. If a motorhome - keep drapes closed on the windshield. That lets a lot of cold in.
