Different Kinds of Window Insulation

Windows provide views outside and ventilate homes.

The windows in a home may be responsible for half the heating and air conditioning costs associated with homes--especially in older homes where the windows may not have tight seals or dual-pane glass. There are different ways to insulate windows, some of which enhance the decor of a room while cutting heating and cooling costs, without replacing windows.

Window Construction

Window manufacturers use different construction techniques, glass and gases to insulate windows. The National Fenestration Rating Council reports that window manufacturers use different properties of glass depending on climatic characteristics. Windows with low U-factor ratings, also known as thermal transmission, keep heat inside a building, important in cold climates, while a low solar heat gain coefficient window reduces cooling costs in hot climates. Sometimes dual-pane windows contain argon or krypton gas to reduce the heat or cold transferring through the glass into a home.

Drapes

One of the most decorative ways to insulate windows is to hang drapes over the window and close them when the weather is either hot or cold to keep the sunshine or air from radiating into a room. Lined drapes or foam-backed drapes insulate the best. Drapes closed on the top with a transom and tightly closed at the bottom, the sides and the middle reduce infiltration effectively.

Plastic Film

Plastic film provides a way to keep air leakage or sunshine from entering a home. Temporary, clear plastic film kits use tape or clips to cover the window from the inside, keeping drafts from entering the home in colder months. Permanent window film has reflective properties that bounce the sunshine back so that the heat from the summer sun does not penetrate through the glass.

Screens

In hot climates, shade screens installed on the outside of windows prevent sunshine from heating the home on windows exposed to direct sunshine. According to Salt River Project, a major utility provider in the Phoenix metropolitan area, sunshine coming through the windows accounts for 50 percent of the heat gain in homes. Sun screens block direct sunshine from entering and do darken rooms somewhat. The shade screens also add a measure of privacy from the outdoors, since people cannot see in during the day, although people in the home can see out.

References

• National Fenestration Rating Council: Questions About Buying New Energy Efficient Windows
• Lower My Energy Bill: Plastic Window Insulation Film
• Salt River Project: Preventing Heat Gain
• Energy Star: Frequent Questions
• California Energy Commission: Prepare for Winter and Cut Your Energy Bills by 75 Percent