What is Low-E?
Low-E is a new window technology that lowers the amount of energy loss through windows by inhibiting the transmission of radiant heat while still allowing sufficient light to pass through. The “e” stands for emissivisty or re-radiated heat flow. The thin metallic oxide coating increases the U-value of the window by reducing heat flow from a warmer air space to a colder glazing surface. The best location for the coating is based on whether the primary heat flow you want to control is from the inside out (heating climates) or the outside in (cooling climates).
Low E stands for “low emissivity”. Low E glass is coated with a microscopic, virtually invisible, metallic oxide layer that improves thermal performance. The primary function is to reduce the U-value by suppressing radiative heat flow. A secondary feature is the blocking of short wave radiation to impede heat gain. Low E is not just effective at keeping heat out in the summer, but at keeping heat in in the winter time.
Low-emissivity, or Low-E, refers to a type of glass that has a coat of micro-thin metal applied. This coating reduces the heat transmission of your glass. In the summer, Low-E reflects the sun’s heat, keeping your house cool. During the winter, Low-E keeps your warmth inside. Low-E does not effect how much light gets into your house. Only the sun’s heat, not its light, is being kept out. You cannot see the coating of metal on your windows. The view is kept crystal clear. Note that Low-E glass is not the best glass if you live in a very cold climate. Anyone who lives in the far north and needs the heat from solar gain (and thus doesn’t need to cool their house), should look into Hard Coat Low-E glass. This glass lets in more of the sun’s warmth, helping to heat the home.
