Most homeowners enjoy the light, solar warmth and scenery that windows provide. But during the summer, excessive heat and glare may compel you to forgo the view and draw the drapes. There is another solution: With insulating window film, you can block harsh rays and still enjoy the daylight and the scenery.

Window film allows light to enter but tempers the sun’s heat, saving energy and making your living space more comfortable. It also protects your home’s interior surfaces and furnishings from damaging UV rays. Some types of film even enhance privacy, safety and security. Although most are available only through dealers, a few manufacturers offer products for DIY application.

Some of today’s windows have builtin low-emittance (low-E) and low-solargain coatings. But for many homeowners with older windows, applying film is a more attainable method of tempering the sun. When properly applied and fully cured (about seven to 10 days later), it creates a practically invisible coating that is durable, though not as hard as glass — check the manufacturer’s instructions for recommended cleaning practices.

The clear facts
During the energy-conscious 1970s, reflective films created to control solar loading from the outside inspired the even DIY-friendly — window film. Today’s products, which do more than reflect solar radiation, fall into these categories:
• Solar-control window films save energy and money. According to Gila (pronounced heela) Film Products, tests show significant savings in the cost of
cooling and heating homes when film is applied. Savings vary, depending on climate and on the efficiency of the untreated windows. Though improvements are more dramatic on single-pane windows, Gila says that its film will also enhance the performance of energy-efficient low-e windows. And the benefit isn’t just for summertime; solar-control films also help to retain indoor heat during winter.
Made of a metalized layer and polyester film, solar-control films block as much as 99 percent of UV light, helping to control glare, lessen exposure to UV radiation and minimize sun damage to furniture and flooring. (For comparison, a standard 1/8-in. single-pane clear glass window blocks about 29 percent of UV rays, and a standard 1/8-in. dual-pane window blocks 44 percent.)
• Safety window films increase shatter resistance, protecting against severe weather, earthquakes, vandalism and break-ins. Frosted or reflective films offer privacy — also a safety feature.
• Decorative films enhance design and architectural interest and provide privacy without darkening the home’s interior. (See “Instant Privacy,” November/December 1999, p. 24, or go to Web Extra to learn more about decorative films.)


All types of window films are available for residential and commercial use (and for automotive applications) as dealer-installed products. Some can be applied by DIYers, saving at least $3 a square foot on labor, according to Dean Jarrett, product manager for Gila Film Products. And because many professional installers charge a minimum fee of $200 to $300 for a job, the cost per square foot for small projects rises even higher. Gila film, which we used for our project, costs about 80 cents a square foot.


DIY or pro?
Although DIY installation is a clear money saver, it requires composure and attention to detail — and a fair amount of time if you intend to cover all of the windows in a house. Windows that are exotic shapes (hexagons, half-rounds, etc.), glazed directly into concrete or brick, very large or in hard-to-reach locations are best left to a professional because handling the film, spray solution and tools can be awkward — sometimes requiring more than two hands. The International Window Film Association offers a list of manufacturers and dealers with certified installers.


In addition, if you’re unsure of a window’s ability to withstand heat stress because of its age or condition, you should consult a professional about film application. Some indications that your window is not a candidate for film include:
• Cracks or flaws in the glass
• Broken seals, which are indicated sometimes by fogging or condensation between the panes
• Dehydrated glazing compound
• Glass that is more than 40 years old.


Before you begin
Window films are safe for all types of glass windows that are in good condition. It’s important to start with a per-fectly clean window and to work in dust-free conditions. Clean and vacuum the room a day before installation to minimize airborne dust. During installation, turn off ceiling fans and the fan on your HVAC system, if possible. In addition, schedule the installation to avoid direct sunlight or temperatures below 45 degrees.

Clean the window with the water/soap solution recommended for the window film application (see the manufacturer’s instructions). Scrape the glass with a single-edge razor, checking that the edges and corners are clean. Reapply the solution and squeegee downward; repeat if needed. Wipe the gasket with a lint-free cloth or coffee filter to remove any dirt and moisture.


If you’ve ever installed wallpaper, you’ll have an advantage in handling window film. Though film is considerably more delicate than paper or vinyl, film panels for windows are usually smaller and therefore easier to maneuver than typical strips of wallpaper. Nevertheless, it’s wise to enlist a helper when you peel off the liner and spray the soap solution onto the back of the film, especially if the window is as large as a patio door.


Once the window and the room are prepared, unroll the film on a flat, clean surface, and trim the film with scissors or a utility knife so it is 2 in. wider and longer than the pane. See the how-to photos shown in this article to learn basic installation steps. The manufacturer’s instructions will also provide helpful tips and complete details.

Looking ahead
After you’ve applied the film, the glass will look hazy until the film and adhesive fully cure. Small bubbles will disappear in six to 10 days. For future cleaning, do not use anything sharp or abrasive to scrape the surface. Always follow the manufacturer’s instructions for recommended care.
When properly installed and cleaned, window film will look good for 10 years or longer and can be removed with a special adhesive-dissolving spray. In the meantime, you can enjoy the view and save energy — without living in the dark.

STEP-BY-STEP INSTRUCTIONS

Step 1: Remove the protective liner from the back of the film. At a corner, use clear tape to separate the two layers (inset). Handle the film with care —creases will not disappear. Spray the solution on the adhesive side of the film, and spray your hands as well, to allow easier handling.

Step 2: Respray the window and apply the adhesive side of the film to the wet glass. Maneuvering the film carefully, position the top edge and allow the film to lie against the glass. Use your wet hands to smooth and slide the film in place, leaving a 1-in. excess at the edges (inset).

Step 3: Spray solution on the film. Use a squeegee to press out water and air bubbles to within 2 in. of the ends. If the squeegee drags, rewet the surface of the film.

Step  4: Trim the film 1/16 in. from the edge of the glass. The slight gap helps air bubbles to escape as you squeegee the edges and allows for thermal expansion of the glass. Rewet the surface and use the squeegee to remove the remaining solution and bubbles.

 

SOURCES

Concord Window Films, 866-743-4561 Gila Film Products, 800-528-4481 International Window Film Association, (276) 666-4932