Low-E glass means the Low-Emissivity Glass which is a type of energy-efficient glass for building. In general the energy of sunlight, infrared heat holds about 51.2%, visible light occupies about 46.8% of the heat, ultraviolet and other rays occupy about 2%, so infrared light is basically heat. The traditional coating glass and colored glass are mainly based on reflection and absorption of visible light. But Low E glass has the ability to allow visible light to pass through glass while blocking certain amounts of UV light and IR light. So its optical performance is greatly improved