Solar Window Film

Using Window Film

By Leigh Hanlon, Tribune Brand Publishing

Making your home more energy efficient can involve projects such as covering your roof with solar panels, erecting a backyard wind turbine or installing a new air conditioning system. However, there are other simpler, less-expensive strategies that can make a major dent in your energy bills, too.

Window film is one such home improvement. Properly applied, window film can cut your household cooling costs by almost one-third. That’s a big deal in Florida, where the U.S. Energy Information Administration (EIA) estimates residents spend 40 percent more than the rest of country on their electric bills while using four times the national average for air conditioning. In fact, Florida is second only to Texas in total residential electricity use.

The EIA’s 2009 Residential Energy Consumption Survey found that 27 percent of the energy used in Florida homes goes for air conditioning. According to Darrell Smith, executive director of the International Window Film Association, window film makes a lot of sense for homeowners eager to save money on their power bills.

“Solar-control films can block as much as 80 percent of the solar heat coming through glass into a building, decrease the heat load on the air-conditioning system and reduce energy costs,” Smith says. He estimates that professionally installed window film can cut those costs by up to 30 percent.

In homes, film is usually applied to the interior surface of the window. The film can be almost completely clear, or darker to reduce glare and provide extra privacy. Some films even feature patterns and designs — and a few even mimic stained glass.

Although window film is a passive, low-maintenance, energy-saving project, the product itself is by no means low-tech. The film consists of from six to 14 layers of polyester that have been treated chemically or with a metallic deposition process. The finished film is 1½ mils thick — that’s 1½ thousandths of an inch. “It’s complex to manufacture,” Smith says. “The thought that it’s just a sheet of shiny plastic is not true.”

Window film first entered the consumer market as a luxury add-on for cars, trucks and vans in the late 1970s, then worked its way into commercial buildings, where its familiar reflective sheen graced many skyscrapers. In the 1980s, the automotive market really took off when the Sun Belt’s booming population bought window film to cut glare and keep car interiors cooler. From there, window film quickly established itself in homes, where today the product meets the demand of cost-conscious owners looking for energy-efficient, green solutions, Smith says.

Window film not only saves energy, it can keep what’s in your home from suffering the ravages of ultraviolet light, which can cause carpets, furnishings, fabrics and artwork to fade or discolor. Smith estimates that 40 - 60 percent of color fading is caused by UV exposure.

“The great aspect of most window films is that they aid in blocking up to 99 percent of harmful UV rays, which reduces solar heat gain,” says Gregg Sampson, a conservation coordinator with Orlando Utilities Commission. “By controlling the direct sunlight that enters the home, it improves comfort and maintains temperature consistency in the home.”

Sampson recommends that homeowners install film on windows that face east, west and south. “We offer rebates to our customers if the shading coefficient (SC) is 0.5 or less (SC is the measure by which shading materials are rated). The lower the coefficient the better it is for providing more shade in a room,” Sampson says.

One final piece of advice about installing window film – you’re probably better off leaving the job to a pro. “If someone is very good at installing wallpaper, they could be good at installing window film,” Smith says. Everyone else should rely on a professional. Just remember the frustration you experienced when you tried to apply a dust-and air-bubble free protective film to your smartphone or tablet. Now imagine trying to do the same thing to a surface the size of a pool table.