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Secondary Glazing

Consider exterior or interior storm windows as an alternative to insulated glass. A well-built storm window system with single paned windows has been shown to be as energy efficient as replacement multi-paned windows.

Storm windows are an awfully expensive substitute for caulk. Caulking, weather-stripping, and reglazing are all inexpensive do-it-yourself procedures that should be done WHETHER or NOT you buy storms. After you’ve stopped the air leaks, you may find that storm windows are not a high priority.

Infiltration, exfiltration

GPL priorities

Also be aware that adding storm windows merely changes the R-value from .9 to 2.0. (The average uninsulated wood-frame wall is R-4.5)


Poor fitting, single-pane windows can lose energy much faster than modern multi-glazed low-e windows. In extreme weather, such a poor performing window may lose energy ten times faster than an equal area of wall. On clear summer days, an unshaded window adds greatly to undesirable solar heat gain. In many homes, heat loss and gain through and around windows accounts for more than 25% of a home's heating and cooling bills. .

. . . Even though storm windows add little to the insulating performance of single-glazed windows (that are in good condition,) field studies have found that they can help to reduce air movement into and out of existing windows, and thus reduce heating and cooling energy bills.

Storm Windows, Energy Efficiency and Renewable Energy, U.S. Department of Energy


The Truth About - Windows and Storm Windows too!, Plainfield [NJ] Historic Preservation Commission

3.0 Windows, Design Guidelines for Residential Historic Districts in Salt Lake City, Salt Lake City Historic Landmark Commission, Salt Lake City Corporation, 1999.



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