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Window Film

Improve energy efficiency, reduce solar gain, and block ultraviolet radiation

Contractor working with window film.

The increasing usage of glass in today's homes is unmistakable. Besides the benefits, some of the side effects are glare, rapid fading of carpets, furniture and draperies, heat build up and higher energy costs. Manufacturers offer window films that improve energy efficiency, reduce solar gain and block ultraviolet radiation. The films allow a variety of applications, finishes and coatings for all types of glass.

The films are manufactured using a sputtering process, which applies metal alloys to the base film. The finished product is a laminate of polyester and metallized coatings bound by adhesives. Most of the sun's heat is transmitted in form of invisible infrared and ultraviolet radiation. The films are able to isolate and reject heat in these energy bands, while allowing visible light to pass through. The visual effect is soft-glare-corrected and color neutral. By applying the micro-thin film to the inside of glass windows and doors, the product can cut from 9 to 93 percent of the incoming light, eliminate up to 99 percent of harmful ultraviolet radiation to protect fabrics and finishes, and cut up to 76 percent of solar heat gain through the glass.

Energy Efficiency

Window films can reduce the amount of solar heat gain entering through the windows, which can be beneficial to summer cooling costs. They can also increase the ability of the window to transmit heat through conductance, helping with winter heating costs.


The nationwide network of qualified dealers can be obtained by calling the numbers included with this entry. Some manufacturers also offer training seminars. Ammonia based window cleaners should be avoided on coated glass. Replacement is difficult and labor intensive. Application to an insulated window unit may aggravate the expansion and contraction of one side of the glazing, increasing stress of the glass and seal. Heat and lighting requirements may also have to be redesigned due to the film's light and heat reducing properties.

The film ranges from $3 to $12 per square foot.

Not Applicable

Courtaulds Films has been ISO 9001 certified.

Not Applicable

A scratch resistant film made by Courtaulds allows installation on both new and retrofit projects. The company claims that while not disrupting normal inside activities (work space: minimum of 3' in front of the windows) the film is applied within minutes with the aid of a surfactant, which activates the Clear Distortion Free adhesive system and then trimmed to size. Maintenance is recommended with mild cleaning solutions whereas ammonia-based cleaners should be avoided.

Warranties can vary from 5 years to lifetime, depending on manufacturer and material used in film.

Compared to conventional indoor solar protection and controlling devices such as shutters, shades or draperies the window films not only maintain the unobstructed window but are an effective and economical method of conserving glass energy loss and increase indoor comfort. Double and triple pane windows can also help reduce energy loss but may not be as effective, despite their higher cost.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.