The term solar film can refer to one of two different technologies. The first is a photovoltaic technology that typically uses thin, often flexible, substrates of metal, plastic, or other materials to create thin and light solar power cells. The second technology is a thin, reflective film for application to the windows of a home. This film reflects heat-generating energy waves, such as infrared, away from a house while allowing visible light to pass. It improves the power efficiency of a home by reducing the energy needed to cool the home in the summer or in a warmer climate.
Photovoltaic solar film, also called thin-film photovoltaic cells, was developed for the primary purpose of integration into the construction of buildings. The cells in the film are created by applying thin layers of a photo-reactive material, often only several nanometers in thickness, onto a thin substrate, or base, material. This contrasts with traditional solar cells created using crystalline silicon, which is essentially a heavy, glass-like material.
Another advantage of solar film-type solar cells is that they can often be applied to existing roofs. Traditional cells are so heavy and fragile that they require a separate supporting structure to hold them in place so they do not flex or shift in the wind. This also often involves redesigning the roof itself to bear the significant amount of additional weight created by the cells and the structure needed to hold them.
The process of installation for solar film is frequently nothing more than simply laying the film down on the existing roofing material, then securing it with screws or other simple fasteners. This also makes solar film-based cells much easier to incorporate into a new building’s design. Though they are often less efficient in creating electrical power than their crystalline cousins, the versatility, lightness, and ease of installation of solar films often makes them either the least expensive cells to install or the only type of cells that can be installed.
The second technology using the name solar film is a relatively simple plastic-based product. Typically, it comes in rolls or sheets and contains additives that either block or reflect portions of the sun’s energy. These films are applied to the windows of a home or other building where they prevent a significant amount of heat-generating energy from entering. In this way, they lower air-conditioning costs and save energy. They are typically inexpensive and often an integral part of newer widows with high energy-savings ratings.