The movie premier of Casablanca took place this day in 1942. At the end of the movie, Bogie got cold feet and sent Ingrid Bergman off into the misty night. If you’ve got cold feet at your casa, the culprit probably is outside air infiltration. You’d be amazed how much fuel a furnace consumes to warm the cold air that seeps into your rooms. Today you’ll learn about measuring drafts from chilly air leaks and tiny cracks. Here’s how: Starting in rooms you use the most, set a large outdoor thermometer down on the floor. Later check the temperature up near the ceiling. If the difference is 10 degrees or less, your room is fairly tight with regard to air leakage. If it’s higher, 15 to 20 degrees different or more, it’s time to start adding weatherstripping and caulk. For each room in your home, just “play it again, Sam.” Once you’ve plugged the leaks (and warmed your feet) you’ll notice fuel bills will be lower.