Windows are rated by a U-value, which indicates the windows insulating ability. The lower the number, the better the window is at preventing the transmission of heat. The U-value of a window is based on the number of glass panes, the thickness of air space between the panes and the type of window frame.
• Check windows for cracks, damaged frames or seals, rotten wood, missing putty, poorly fitting sashes, and draft.
• For a temporary but quick fix before the winter hits, you can purchase storm-window kits consisting of plastic film you tape to the inside of your windows. The kits are available at most hardware stores for $3 to $8 per window. They usually last for one to three years.
• You can reduce heat loss through windows by installing insulated curtains or drapes on a windows interior. They help keep heat in during the winter and out during the summer.
• In the winter open the curtains during hours of sunlight to allow natural heating, and during the summer keep the curtains closed or add an UV film to help keep the heat out.
• During the summer, when possible open two or more windows at night and early mornings when there is a breeze. Opening a window on each side of the house will help with circulation and offer better cooling.