Conscious Choice: Low-E Window Film

October 1999 | Sensible Home

Low-E Window Film

by James Dulley

Dear Jim: My budget is limited, but I have to do something to block the sun’s heat and glare through our windows. It is ruining our carpeting, too. What do you think of the low-cost, nearly clear window film kits? — Pam H.

Dear Pam: Applying window film would be a good solution to overheating and fading even if you were not on a limited budget. You will also be surprised at how pleasant it is to be in a room without harsh glare from windows. With normal window care and cleaning, the film may last ten to fifteen years. Many of the newer window films, especially the do-it-yourself low-emissivity (low-e) film kits, are nearly clear. If you walked into a room with the film installed on all the windows, you would not be able to notice it. The reduced glare would be your only hint. The reduction in your air-conditioning electric costs will be noticeable. Generally, without the intense radiant heat and glare from windows, you can be very comfortable with the thermostat set several degrees higher in the summer. This can result in up to a 10 percent electricity savings. Low-e properties work in reverse in the winter and keep heat indoors for year-round savings.

Furniture and curtain fading has many causes, including ultraviolet (UV) rays. These include visible light, heat, and other factors. Window film will block nearly all of the UV rays and varying percentages of the other causes depending on the tint and properties of the film that you select.

You can buy either do-it-yourself film kits or have it professionally installed. Many of the professional films use a sputter method of applying microscopic metal particles. They are invisible, but they block heat. The lower-cost films use an aluminum-vacuum deposit method. This makes the film slightly more reflective, but very effective. It creates a low-e coating similar to new replacement windows. The film has a water-activated adhesive on one side. If you can wash a window, then you can easily install a window film kit yourself. And the film can be easily removed years later using water or special film removal solution.

All window films make glass shatter-resistant for safety during storms or around your children. On other scales, however, different window film kits perform differently. Be sure to compare their properties, including their emissivity, shading coefficient, and visible light transmission. Lower emissivity films are best for year-round comfort and savings. Lower shading coefficient films block more heat. Lower visible light transmission films block more glare, but can make the window darker.

Write for (or instantly download) Update Bulletin No. 973, buyer’s guide of do-it-yourself (plus a small sample) and professional films, properties, prices, and installation instructions. Please include $3.00 and a business-size SASE. James Dulley, Conscious Choice, 6906 Royalgreen Dr., Cincinnati, OH 45244

Recommend this page to a friend

Top Ten pages recommended to friends: