Solar heat gain through windows accounts for up to one-third of the cooling costs in a building, according to an annual publication from the U.S. Department of Energy. Window film and solar screens are two options that are often used when it comes to controlling solar heat gain to reduce electric bills and save energy.
Solar screens are fixed, framed panels made of dense mesh or fabric that are mounted on the exterior of a window. They serve the same purpose as window film: to stop heat transfer and block UV rays. The specialty mesh or fabric blocks harmful rays and reduces glare, which can improve energy efficiency, prevent furniture and carpet from fading, and stop UV rays from penetrating the glass. Some solar screens are permanently attached to windows, while others are removable.
The dense mesh used in solar screens can affect how a building looks from the exterior; it can also affect views from inside. The type and thickness of material used in a solar screen can also block airflow through an operable window, which is a factor to keep in mind if opened windows are used to provide ventilation or control temperature. Solar screens tend to collect dirt, debris, and bugs, which means they need to be cleaned often to prevent further view distortion. Because different weave densities are available, solar screens are rated by “openness factor” (a measure of how much they obstruct views).
Just like solar screens, window film improves energy efficiency, stops fading, provides protection against UV rays, and reduces glare. Window film is a laminate made of strong polyester and metalized coatings bonded by adhesives. It can be clear, colored, reflective, or patterned, and is available in a variety of selections (security film, low-e film, etc.). When solar radiation hits the window, window film reduces UV rays and regulates the heat and lighting levels that pass through.
Window film usually doesn’t block views to the outside like solar screens do, so tenants/occupants don’t lose sight of the outdoors. It doesn’t collect dirt or debris, so it can be cleaned less often than solar screens. Low-e window film also allows for energy savings year-round, reducing heat loss in the winter and both solar and non-solar heat gain in the summer. It reduces the heat entering in the summer months, and retains certain heat during winter.
Have you used solar screens or window film on your commercial building? What benefits did you see as a result?