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.
Brass or bronze flanges are secured along one edge and then sprung along the other to press tightly against the moving sash.
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
Integral weatherstripping has a metal strip with a rigid fold that is nailed to the jamb and inserted into channels cut into the sash.
Soft, ribbed, adhesive-backed foam is easily applied to the bottom rail of the sash.
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.
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.
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.