Low-E coating

A Low-E coating is a layer of metal oxide or silver, often only a few nanometers thick, deposited on one or more surfaces of a glass pane. The name comes from "low emissivity," which describes the glass's reduced ability to radiate heat. Light passes through the coating, but infrared heat is reflected back toward its source, and most ultraviolet light is blocked.

The coating matters most in skylights because the roof is one of the largest sources of solar gain in a building. In Citrus County, where summer sun is strong and cooling costs run high for much of the year, a skylight without a Low-E layer can let in a lot of heat and UV that fades floors, furniture, and fabrics. A Low-E coated unit keeps more of the sun's heat outside while still giving you daylight.

Low-E coatings are usually applied to the inside of an insulated glass unit, which is why they are sealed between panes and do not wear off with cleaning. Manufacturers often describe the coating in terms of its solar heat gain and visible light transmission, so the two numbers can be compared between products. If you are looking for installers who work with these units, the skylight replacement providers listed in this directory are a good starting point.

Low-E is one feature among several in a skylight, alongside frame material, glazing type, and the number of panes. It is best understood as the surface treatment that controls how the glass handles heat and light.

Commonly listed alongside: insulated glass unit, solar heat gain coefficient, visible light transmittance, UV filtering.