Low-emissivity (low-e) coatings applied to glass reflect invisible long-wave infrared (IR) energy, or heat. They reduce heat gain or loss in a building by redirecting the heat. Low-E coatings are typically placed on the outside surface of the laminate and sputter coatings face inward and directly touch the interlayer. Some manufacturers can do a flexible both ways installation. The coating can be applied in almost any type of glass.
Low-e glass stands for low emissivity glass. This glass varies from normal clear glass in that one side of the glass has a special metal coating, technically known as a low emissivity, or Low E. coating. Low-E glass is a type of insulating glass, which increases the energy efficiency of windows by reducing the transfer of heat or cold through glass. That means in the winter your house stays warmer, and in the summer it stays cooler.
There are two types of Low-E (low emissivity) glass available: hard coat and soft coat.