Wendy Tremayne shows how easy it is to open and close curtains for passive solar heating. Her home heating bill has never exceeded $45 for a 1,100 square foot uninsulated trailer. The night time temperature that this film was made was down to 6F with windchill and day time high was only 36F. No heating was required during the day and the home heating unit only kicked on 3 times for 15 minute runs during the night to maintain a stable 60F indoor temperature.