Want to see how drafty your home is, or want a foolproof way to detect air leaks in your home? Start by turning off all combustion appliances in your home, like gas-burning furnaces or water heaters. Do this on a cool, very windy day. Shut all the windows, doors and fireplace flues. Make sure all fans, clothes dryers and vents are totally off, too. Try to make your home as airtight as possible. Now light a stick of incense. Follow the smoke, and see where it naturally wafts. If you find an area you suspect has a leak, use a wet hand to locate it; the water will feel very cool and should lead you right to the energy-hogging leak.