Energy savings can be obtained with the use of window film. Window film reduces the amount of heat that enters a room. Less energy is required to cool the room. In the winter, the film acts as an extra insulation on the window, reducing heating costs. LEED credits can be obtain by using window film. The number of points that are obtained, depend on the amount of energy saved.
The goal of this credit is: Achieve increasing levels of energy performance above the baseline in the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use. (www.3M.com/windowfilm)
There are 3 different methods for achieving this requirement. Up to 10 credits can be obtained depending on the amount of energy savings. For specific information on the methods see the sustainable design information sheet in pdf form on the 3m web site: multimedia.3m.com/mws/media/6636910/sustainable-design-information-sheet.pdf
Window film is a first tier technology that can have an approximate 3 year payback for buildings. Window films are ranked in retro-fitted building envelopes as having the highest probability of success. It ranks above replacement windows. Already existing materials are used decreasing the amount of waste. (https://promo.3m.com/assets/3MCAN/1202511082.pdf)