Low-e films protect against UV rays.
Energy-saving construction materials are becoming increasingly more available as homeowners look for different ways to save money throughout their homes. One of the most popular ways is by insulating the house well enough to prevent heat transfer to and from the outdoors. Low-e windows are designed to both protect materials within the home and significantly lower energy costs by sealing windows, one of the primary heat loss locations.
Definition
Low-e stands for low-emissivity, which means that the window allows only certain types of light to pass through. The film blocks a large amount of ultraviolet, or UV, light before it can pass through into the house. Not only does UV light carry a lot of energy to add unwanted heat during the warmer months, but it can also damage some types of drapes, furniture or carpet through repeated exposure. Low-e films are designed to give windows a barrier to prevent these problems.
Materials
The film is actually a very thin layer of plastic coated with some type of metallic element or metal oxide. This metal compound stops the UV light from making it through the film, while allowing other wavelengths to pass through with no reaction. Some windows can be bought with the film already installed, while other films are available for being bought and applied to existing windows. However, they will diminish some of the natural daylight entering the windows.
UV Light Admittance
Low-e films work on two levels at the same time: reflection and absorption. The metal elements are designed to provide a semireflective surface that will dissipate some of the solar heat in the UV rays before they even make it through the film. The metal elements will also absorb the energy in the photons instead of letting it pass into the atoms inside the house. Makers claim that good films can reduce solar heat by 80 percent to 90 percent.
Types of Tints
Different tints are available in different film strengths. Some only partially block out solar heat but allow more light into the house for a more natural appearance. Other films block out the maximum amount of heat possible and tend to be the most expensive versions. Some films offer addition benefits--side-effects from reducing UV rays--such as less glare and increased privacy.
Lifespan and Alternatives
A good window film will protect a window for about 10 to 15 years before it will need to be replaced. To skip this replacement step, homeowners can buy windows that have UV coatings painted on the window itself or even fused into the glass. If homeowners prefer natural sunlight, they can buy windows that have sealed, gas-filled spaces between their panes, which stop heat transfer while letting UV light in.
Tags: Low-e films, pass through, solar heat, through film, heat transfer, into house