To repair a foggy insulated window, measure and adjust the humidity in the affected area, replace damaged caulk and weather stripping, and cover the window with clear plastic sheeting. To complete this task you need a hygrometer, a putty knife, latex caulk, a caulk gun, weather stripping, tape and clear plastic sheeting.
- Measure and adjust the humidity
Measure the household humidity with a hygrometer. If it exceeds 40 percent, decrease it by opening windows, unblocking air vents and opening heavy curtains. Reduce the operation of the laundry machine and dishwasher. If the house has kitchen and bathroom exhaust fans, turn them on while cooking and showering.
- Replace the caulk and weather stripping
Remove the existing caulk with a putty knife, and pull up damaged sections of weather stripping. Load a caulk gun with latex caulk. Pipe it over the juncture between the window frame and the wall, and then use it to fill small cracks in the wall, floor and ceiling. Place new weather stripping on the window sash where it touches the frame.
- Cover the window with plastic
Let the caulk dry according to the instructions on the package. When it is cured, tape a sheet of clear plastic over the window. Large windows require multiple sheets.