Tinted windows are common on office buildings and store fronts, but they're relatively new for the home.

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­Driving up next to a limousine can make you wonder who is inside -- a celebrity, an athlete or a newlywed couple. While the passengers are probably more interested in privacy, the dark-tinted windows also offer them protection from the glare and sun. Much like cars, window films are now being used in residential settings to offer homeowners the benefits of a sun filter to block some sunlight, while allowing other light into the home.­

Sunlight can be helpful when it's aiding in plant growth or warming the Earth. Yet these same characteristics of heat and light can also make it a nuisance. In particular, infrared, ultraviolet and visible light rays are the primary concerns when it comes to sunlight affecting people's lives. These types of solar radiation are all part of the spectrum of light that makes it through the Earth's protective atmosphere. Infrared and ultraviolet light rays are invisible to the human eye [source: The Kingfish Science Encyclopedia]. Infrared light carries heat energy, while ultraviolet light is the radiation associated with sunburns. Visible light is made up of the many wavelengths of light that allow us to see different colors.

­For centuries, people have been devising ways to shield themselves and their possessions from the sun. Starting with bonnets and sun umbrellas, then moving to sunglasses and sun-protective clothing, people have been inventing new ways to deal with the ever­-present solar radiation.

In the 1960s, a new technology called window film came on the market. Since that time, the technology has continued to evolve, offering homeowners another option for protecting their family and property. These advances in technology now allow for window films that can block a significant amount of heat energy while still allowing the homeowner to enjoy a virtually unimpaired view from the window.

In this article, we'll look at what a window tint is and how to evaluate various window tints, costs and maintenance.