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Upgrading to ENERGY STAR-rated units can lower your monthly utility bills up to 15 percent, according to the EPA. For maximum efficiency, consider dual- or triple-pane units or those that are argon-gas filled with low-E coatings and a low U-factor (the lower the U-value, the better).
If replacing existing windows isn’t feasible, upgrade efficiency in current units with simple steps like caulking and weather-stripping around air leaks and adding a protective solar film, exterior shades or UV-diffusing window coverings.
There are plenty of good weatherstripping options to choose from, depending on where your window needs it most.
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Brass or bronze flanges are secured along one edge and then sprung along the other to press tightly against the moving sash.
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Polypropylene or nylon flanges have a barbed leg that inserts securely into slots cut into the stop moldings, jamb or sash; their “spring” is shaped during manufacturing.
See also Air Sealing Your Log Home
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Integral weatherstripping has a metal strip with a rigid fold that is nailed to the jamb and inserted into channels cut into the sash.
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Soft, ribbed, adhesive-backed foam is easily applied to the bottom rail of the sash.
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Interlocking metal weatherstripping consists of two opposing U-shaped metal strips designed to cup together and provide an airtight seal between the meeting rail’s mating surfaces.
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Thin compression silicone tubing can be applied mechanically in a slot, or via adhesive, to seal the smallest gaps between meeting rails without affecting locking mechanisms.
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Thicker silicone compression tubing attaches to the top of the upper rail to accommodate larger gaps that develop as a result of house settling and paint buildup.