Window films are thin layers of polyester, metallic coatings, and adhesives that save energy by limiting both the amount of solar radiation passing through the window and the amount of internal heat escaping. High-reflectivity window film helps block heat gain from direct sunlight during hot summer months. They can be applied directly to the interior surfaces of all types of glass for existing windows.
Window film makes the most sense in hot climates with longer cooling seasons and on windows that are most likely to receive direct sunlight because the film also blocks heat from sunlight during the colder months as well as limits light permeability year round. Energy Savers recommends that east-facing and west-facing windows can benefit most from using window film, that south-facing may benefit somewhat, but may be outweighed by the loss of heat from winter sun, and that north-facing are not likely to derive much benefit at all. For more information, please see Energy Savers or Energy Star
To check if there are any incentives or rebates available for this product in your area, please visit the Database of State Incentives for Renewables and Efficiency (DSIRE).
Spectrally selective window films. >= 70% visable light transmission recommended.