Low-E, or low emissivity, glass decreases the emission of heat transfer. Windows with regular glass let in about 74% of sunlight and other natural heat sources. High-performance Low-E glass, on the other hand, reflects heat back to its source, cutting the amount of heat transfer in half. Watch this video for a demonstration of how Low-E glass can block heat transfer. With advanced Low-E glass in your windows, you can actually block 97% of total thermal transfer. Not only does this feature help keep your home cool in the summer, but also insulates warm indoor temperatures during harsh Michigan winters, which lowers your energy costs dramatically.