Window tints can be evaluated on a number of different criteria depending on the goals of the homeowner. One window film might offer more heat reduction, while another window film might provide more privacy. Window tints have many beneficial qualities, but there can be a trade-off. Knowing how to evaluate these qualities can help you make your final decision.

Energy savings can be one of the most important criteria in choosing a window film. In new homes, windows can cause about 75 percent of heat gain during the summer months, which drives up air-conditioning costs [source: Morrill and Wilson]. This heat gain can also affect your overall budget. According to the U.S. Department of Energy, 45 percent of a typical utility bill is dedicated to heating and cooling [source: U.S Department of Energy].

The amount of energy savings is dependent on a number of factors, including tree shading and the orientation and location of the house, along with the type of film used. When evaluating the ability of a film to reject heat, first you must look at what's causing the heat. Most of the heat from the sun comes in the form of infrared rays, so preventing those rays from entering the home will help to reduce heat inside the home.

When evaluating heat reduction, there are two important factors to look at in a window film: the solar heat gain coefficient and solar reflectance. The solar heat gain coefficient involves the amount of solar energy that the film is letting into the building. The lower the solar heat gain coefficient, the less heat transmitted into the building. Another important measure is that of solar reflectance, or the amount of sunlight reflected by the film. Films with high reflectance ratings will provide greater heat reduction [source: Solar Gard Window Films].