Heat Reducing Window Film

Apply a simple transparent film to reduce heat gain from direct sunlight

Install special window films to reduce heat gain from sunlight or reduce heat loss in cold weather. It's a quick and easy task.

By the DIY experts of The Family Handyman Magazine

Keep rooms cooler with heat control window film

If you have room that gets too hot from direct sunlight, consider installing a heat control window film to keep the room cooler. These films reflect the sun’s heat and ultraviolet rays, and reduce glare without obscuring the view (see photo). The more direct sunlight coming through the window, the more the film will help (and it may lower your air-conditioning bills!).

Different types of film are available, so get the one designed for heat control. The film can be applied to any window, including double-pane low-e windows, although they already reduce radiant heat loss and gain.

One drawback is that the film may void the manufacturer’s warranty for the seal on double-pane windows, although the film representatives we talked to said the film shouldn’t affect the seal. If the window warranty has already expired or reducing excessive heat is more important to you than possibly jeopardizing a warranty, then apply the film. Otherwise, consider other options, such as installing shades, awnings or shutters over the windows or even planting a tree on the west side to block the sun.

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Buying and installing window film

You can install the film yourself. Applying the film takes approximately 30 minutes per window. It should last about 10 years. Prices vary with film size. A 3-ft. x 15-ft. film (which can cover two to three windows) costs about $30. The film is sold at home centers and hardware stores. Gila is one company that makes heat control film (www.gilafilms.com).

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Utility knife
  • Tape measure

You'll also need a squeegee and scissors.