Dear Jim: The sun’s heat and glare are uncomfortable coming through the windows and it is also fading my furniture and carpeting. Will applying clear inexpensive insulating window film minimize these problems? – Jack N.

Dear Jack: New insulating window films can reduce heat and glare by more than 50 percent and block nearly all the sun’s ultraviolet fading rays through your windows. True insulating window films also reduce heat loss during winter and make sitting by a window more comfortable year-round.

Insulating window films are not totally “clear,” but the tint in some is so slight that when applied to the window glass, it is barely noticeable. All window film makes glass more shatter-resistant and safer around children. Some heavier films can also enhance security against window break-ins.

Window film is available in rolls or single window boxes for do-it-yourself (DIY) application or from professional installers. Installing it yourself can save up to 75 percent of the cost of professionally installed film.

Residential window films are considered permanent because, with proper cleaning, they can last 10 years or more. If you decide to remove the film at a later date, the manufacturers offer removal solutions that quickly dissolve the adhesive. The window glass surface is not harmed.

The primary difference between DIY and professional films from companies that offer both is the type of adhesive used. On all but the largest windows which require more installation skills, DIY application looks as good. Another advantage of professional installation is a long warranty.

True insulating window films derive their energy-saving/comfort properties from a low-emissivity (low-e) coating in the film. This is the same low-e technology used on new super-efficient replacement window glass. This low-e coating is a microscopically thin layer of metal on the film’s inner layer. Visible light passes through it making it invisible.

Heat energy from the sun and reflected from walkways, patios, etc. is a different wavelength than visible light and is blocked by the low-e film. During winter, it also keeps heat indoors.

Energy-saving qualities vary widely for different window films, so don’t just buy the cheapest film on sale. Compare the film properties first.

The emissivity is a key property to determine year-round insulating-comfort value. Shading coefficient indicates how much heat-glare are blocked.

If you can wash a window, you can easily install insulating window film yourself. You purchase the film, in pieces from a roll or in boxes, and a simple installation kit. Most films have a water-activated adhesive on one side.

Write for (instantly download – www.dulley.com) Update Bulletin No. 617 – buyer’s guide of seven DIY (plus a small sample) and professional film manufacturers (34 films) listing savings/comfort properties and installation instructions. Include $3 and a business-size SASE, and send to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244.