Category Archives: energy retrofitting

Reprint from Holmes Magazine.

Q: Our living room’s bow-window always developed condensation and even ice on the inside pane in the winter.  My husband and I assumed it was because it was old, but even after replacing all of the windows in our 1,000 SF house, the problem is still continuing.  Our humidity level isn’t high – it’s generally around 35 percent.  What could be causing this?

A: As the season change, some homeowners might experience moisture forming on the inside of their windows.  Naturally, many think that there’s an issue with the window; but this is actually a sign that the window is doing its job to keep the warm air inside your home.  The condensation is a result of too-high humidity levels inside your home.  For example, in the winter the ideal humidity range is 20 percent  to 25 percent and , in the summer; the level should not exceed 50 percent.  Anything above these levels and condensation may occur, just as a “sweating” is the result of a glass surface that tends to have a lower temperature than most other surfaces in your home.

Ice forming on a bay or bow window can also be due to a lack of insulation under the seat board and above the head board.  Adding insulation, combined with opening your blinds and pulling back heavy curtains to let heat reach the inside pane of glass, should resolve your problem.  Also, lower your humidity and run dehumidifier to get your home into the ideal humidity range.

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