Can I insulate my basement windows using insulation?
The only problem with this plan is condensation. It will be difficult to seal the insulation to the point that you do not get a bit of moist air between the window and the insulation. Since the windows will not be heated, the glass will be cold. This will cause water vapor in the air to condense on the windows and get the insulation wet, which in turn will reduce the effectiveness of the insulation and make a mess. Instead of fiberglass insulation, get some sheets of polystyrene insulation. Cut these to fit the window hole and fit them in place. Friction will hold them if you cut close enough, but use some cheap latex caulk to fill the gaps. This will seal up better and the polystyrene will not be harmed by any moisture that condenses. As an added bonus, these will look much better from the outside. You could even paint the back if this is an issue. These sheets are aviavailable 1/2″ to 4″ thickness, the store you purchase from may not have some of the thicker panels, they are not real
