A Cool Way to Reduce Heat...

QUESTION: I want to install residential window film myself to block the sun’s heat and stop the fading of my curtains and furniture. What type of window film is best so the sun’s heat isn’t blocked in the winter too?

ANSWER: Installing window film yourself is one of the best methods to control the summer sun’s heat and glare. It lowers your air-conditioning costs and improves your comfort. An added benefit is that it blocks nearly all the ultraviolet rays, so it protects your curtains and furniture from fading.

There are many types of window film available and each has its specific sun-control characteristics. Generally, the ones that block the most solar heat in the summer, also block it in the winter. With proper cleaning, window film should last 10 years or more.

There is a special type of residential “insulating” window film that uses a low-E (low emissivity) coating. This low-E coating is the same type of coating that is used on the new super-energy-efficient thermal replacement windows.


It is as effective at blocking the sun’s direct heat as ordinary window film and better at blocking reflected heat from patios and walks.

Although insulating film does block some of the sun’s heat in the winter, it also reduces the heat loss back outdoors. Overall, energy is saved and your heating bills are lower too.

Even if you aren’t concerned about stopping the summer sun’s heat, insulating window film is often a good idea. In addition to the winter energy savings and stopping fabric fading, it increases the shatter resistance of window glass. This is important for children’s safety.

Residential insulating window film is available in several degrees of tint. After installation, you generally won’t even notice the lighter-tinted film on your windows. There are also more reflective insulating window films available that block even more summer heat.


It is easy to install insulating window film yourself. Cut the window film with scissors about 1 inch larger than the window glass area. Using a spray bottle, wet the indoor surface of the window with water.

Peel off the backing, wet film’s adhesive surface and place it against the glass. Position the film on the glass and squeegee it to force out the excess water. Cut the excess film overlap with a razor blade and let it dry.

You can write to me for Utility Bills Update No. 331 for a small sample piece of low-E insulating window film to try on your window, heat-blocking and performance specifications, addresses of manufacturers and do-it-yourself instructions and diagrams. Please include $1 and a self-addressed envelope.