Window Film

A window film is a thin, transparent sheet that can be applied to the interior of a window to change the heat- and light-transmitting characteristics. Films reduce cooling loads, improve shatter resistance, block up to 99 percent of ultraviolet (UV) radiation, and reduce glare. Temperatures near the windows are reduced as well, which can increase occupant comfort. It’s important to note that films are most suited to buildings in hot climates, where they can reduce cooling loads; in cold climates, however, the reduced solar heat gain can increase heating loads.

In retrofit applications, you can apply window films to existing glazings to obtain many of the benefits of window materials that control solar heat gain (Figure 1). Typical films have a total thickness of 0.001 to 0.004 inches; they are made with a variety of adhesives and can be applied on-site to single- or double-glazed windows, usually to the inner surface that faces the room. Some early window film products suffered from fading, color shift, installation difficulties, and poor adhesive performance, but those difficulties have largely been resolved with the newest products and application techniques. Payback periods of less than three years have been reported.

Figure 1: Window films help control solar impact
Window films help block infrared radiation, the major solar heat transfer mechanism. They also block ultraviolet (UV) radiation that causes fabrics and other materials to fade. The amount of visible and infrared light transmitted varies from product to product, but most films block the majority of UV light.
Figure 1: Window films help control solar impact
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