window. Many window blankets (also called ‘window quilts’) will do this. But it’s quite another thing to do the job without also causing lots and lots of condensation on the inside of the windowpanes. This is a very distinct danger in our cold, Canadian climate. The key to preventing this is a blanket design that seals the junction between the window frame and window quilt on all four sides. The best systems I’ve seen include a track on the sides, top and bottom for this purpose.

If warm, moist indoor air is allowed to enter the space between the window and the window blanket, this air will cool and moisture will condense on the glass surface. Sometimes the process of leakage and condensation gets bad enough to form puddles on your floor. Even with a good seal around the edge of the window blanket, expect a little frost to develop on the windows during cold nights. This is normal and harmless.