Mind the Gap

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Cheaper aluminum storm windows are often also installed incorrectly by cut-rate contractors.  It is not uncommon to find large gaps because of improper sizing.  On a recent project, we replaced the old triple-tracks with modern low-e storm windows and upon disassembling the windows, we found up to 1″ gaps not covered by the storms.  Because these windows were on the third floor and not readily visible from the ground or the street, and the upper primary sash was painted shut, this shortcut was never caught, but cold air blew in, freezing the occupants and raising heating bills for many years.