We are fulltimers in a 38' Montana 5th wheel and I discovered that we were air conditioning our basement storage area because of the furnace return grills on 2 of our steps up to bath/bedroom area. Now each spring after we are finished with the furnace for the season, I pull the grill covers and place a piece of luan plywood behind each one. Now all the cool air stays where it should be and the a/c's each run less. I stained the luan to match and you can't tell they're back there. Just be sure to remove them when furnace is needed again in the winter.
