Low Emissivity (Low-E) glass is produced by Magnetron Sputtering Vacuum Deposition technology (also known as "sputtering") layers of coatings, including one or two layers of silver on glass. Silver is the material with lowest emissivity which is a measure of a material’s ability to reduce the infrared radiation. Ordinary clear glass has a surface emissivity level of 0.84, meaning about 90% of the absorbed heat is emitted from the surface. When Low-E coating are applied to glass, the surface emissivity is reduced to less than 0.15.