Sun Stopper

Window film can save money, protect furnishings

Retailers need to show their products. Restaurant owners need atmosphere. Offices benefit from natural lighting. That usually means lots of glass.

But along with the benefits of letting the sun shine in come a few hurdles. "One of the disadvantages of having big expanses of glass is energy loss," says Keith Taylor, WEMC commercial/industrial account representative. "In a commercial building, 50 percent or more of the energy bill may be directly due to heat loss or gain through glass."

Besides big bills, that means air conditioning equipment requires more frequent maintenance and has a shorter life span. The initial outlay for heating and cooling equipment is also higher since it has to be sized to take care of increased space conditioning demands.

If equipment isn't sized properly, the increased solar gain to the building can make customers uncomfortable and decrease worker productivity.

The sun's UV rays play havoc with drapes, furniture and carpets by fading fabrics and damaging woods. And increased exposure to UV rays had been related to some cancers.

Then there's annoying glare. But the answer to all these problems may lie in a thin piece of plastic.

A solar control specialist bonds window film to glass at Walton EMC headquarters. A window film professional can help you choose the right product for any application as well as ensure the film is properly installed. Many films are not warranted unless a certified dealer installs them.

Modern window films are thin polyester sheets with a microscopic layer of metal bonded to them. This metal layer allows visible light to pass right through.

But UV rays and heat energy are blocked from penetrating the film since they're at different wavelengths than light. Window film with this metal (low-emissivity) coating can block up to 99 percent of UV rays. For comparison, a clear single pane window blocks 23 to 28 percent and insulated glass blocks 36 to 41 percent of UV rays.

In the winter, a low-emissivity coating reflects internal heat back to the inside of the room. That allows the window film to save energy all year.

And windows don't have to be dark to take advantage of window film. Some modern films are so slightly tinted that they're virtually undetectable. If you do want an effect, choices include various degrees of tint, dark film for privacy, bronze film for soft lighting and frosted film for a translucent look.

Modern films have an adhesive that's activated when it's sprayed with water. When it comes time to replace the film, a special remover solution releases the adhesive.

Don't look for the cheapest film. Chances are it won't have the low-emissivity coating that provides the year round insulating and comfort features.

When comparing film, check the emissivity figure. Lower emissivities are better. Also look at the amount of solar energy the film rejects.

With the trend of high ceilings and large expanses of glass in residential construction, window film may be the answer to solar problems at home. A professional installer is the best source of information for solutions.

Look for installers who are members of professional organizations, including the International Window Film Association. The IWFA provides certification programs and continuing education for window film professionals. You can go to their web site to find a certified installer in your area.

Modern professional window film reflects solar energy in the summer and keeps internal heat inside in the winter.