Air Leakage
Weatherstripping prevents air leakage through gaps around doors and the moving parts of an operable window. As much as 7-12 percent of a building's heating and cooling loss occurs around windows and doors, so weather-stripping is an important part of your energy-saving curriculum. Effective weatherstripping must close gaps completely and be easy to replace. It should be flexible and allow you to open and close windows and doors easily. Aluminum and vinyl stripping for the bottom of your door is rather inexpensive, fairly easy to install, and will last for several years. Tubular Vinyl Gasket Stripping is used for both windows and doors, it's durable and flexible enough to seal uneven gaps and joints. Foam-Backed Tape is easy to install but it also wears out easily, it is good for windows and sliding doors.
Foam gaskets made to fit behind the cover plates of electrical receptacles, switches and lighting fixtures reduce air leakage.
Caulking is used to seal all gaps around fixtures, openings, door and window frames. Use heavy-duty caulking and apply thick beads of caulk around gaps in the attic, and at the junction between the basement wall and the house. Use roof caulk to seal flashing around chimneys, skylights, rooftop vents, and plumbing risers. Paintable caulking will work well around window-frames, sills and other high-visibility items. Clear silicone caulk will be almost invisible in places that will not be painted, such as the floor-baseboard junction. Peel-off caulk can be used to seal gaps temporarily. Types of Caulking, oil-based caulks are the cheapest, but least durable, and should be used only in narrow cracks. Butyl-based caulks are medium-priced and fairly durable. Acrylic latex caulks are medium-priced, fairly durable, and easy to work with. Silicone-based caulks are the most expensive and the most durable. To fill large cracks or holes, use oakum, caulking cotton, sponge rubber, or fibreglass. Then apply regular caulking in the smaller cracks. Before starting a caulking project, remove any old caulk, clean the surface, and allow the area to dry. Don't caulk if the temperature is below 40 degrees Fahrenheit/5 degrees Celsius. As a guideline, you'll need about half of a caulking cartridge for each windowsill, two cartridges for a two-story chimney, and about four cartridges for a foundation sill. If it's your first time caulking, buy a little more than you'll need so you can practice before starting the project. Cut the nozzle to make a bead just big enough to cover the gap. To store the caulk when you're finished, store the remaining caulk by putting a large nail in the nozzle hole, then wrapping the nozzle with aluminum.
Expanding foam insulation can be used to fill up large gaps in walls. For maximum effectiveness, however, insulating foam must be applied before the weather turns cold. Insulating foam is used to seal gaps larger than 1.27 cm (1/2 inch) across.
