Many of us are concerned with our home's energy efficiency, and for good reason. A leaky house will cost the homeowner more to heat in the winter and cool in the summer. Luckily, there are lots of simple and cost-effective steps the average homeowner can take to seal up cracks in common places, such as around window frames. A bead of caulk around the exterior frame of a window will prevent air from escaping and entering the home.
Locate the leak. The U.S. Department of Energy recommends assessing your windows for leaks before you seal them up. The best way to do this without hiring someone to perform an energy audit is to depressurise your house by turning off the furnace on a cool, windy day, closing all doors and windows and turning on all the exhaust fans. Light a stick of incense, hold it close to the window and see if any smoke escapes or if it's pushed into the room.
Lay a bead of silicone --- either household or construction grade --- around the exterior frame of the window, as close to the union of the window and the house as possible.
Wipe away any excess or misplaced caulk with a wet rag. Water-based silicone caulk will wipe away easily.