You can use weatherstripping in your home to seal air leaks around movable joints, such as windows or doors. To determine how much weatherstripping you will need, add the perimeters of all windows and doors to be weatherstripped, then add about 10 percent to accommodate any waste. When choosing the type of weatherstripping to use, take in consideration that the product can come in varying depths and widths. Choose a type of weatherstripping that will withstand the friction, weather, temperature changes, and wear and tear associated with its location. Additionally, you should note that all windows have a large gap (e.g., ¼ to ½”) on all four sides between the window sash and the framed opening. This is a major source of thermal and air leakage that is hidden by window trim and/or wall finish. For a significant impact on home performance, look for any opportunities to access this opening and fill it with non-expanding foam (expanding foam will compromise the operation of the window) to better seal any air leaks.
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