Low E Glass Windows: A 70's Invention with a Bright Future
By Robert Berge
Until recently, I had never heard of low e glass windows. In fact, even when I first did hear of it, I thought that it might be some sort of gimmick with a cryptic name that essentially did nothing. After researching low e glass windows however, I soon realized how wrong I was.
Developed in the late 70’s, low e glass windows act as insulators. The ‘e’ in low e glass means emissivity. Emissivity is an object’s ability to absorb and radiate energy. Low e glass windows therefore, having low emissivity, do not absorb energy (such as heat, UV, and Infrared rays) well at all, but rather reflect it back to its source. Thus keeping heat in, and cold out in the winter, and cool air in and hot air out in the summer.
Low e glass windows can be divided into two types: hard and soft coat. Hard coat low e glass windows have a thin layer of tin applied to the glass while still in its molten state. Soft coat low e glass has a thin layer of silver applied to it while in vacuum and is sandwiched with another piece of glass. Generally speaking, soft coat low e glass windows are considered the better of the two. For example, while hard coat low e glass windows are easier to handle, they can give off a slight haze. Soft coat low e glass windows on the other hand, are highly sensitive to handling but provide greater optical clarity and insulate interiors better than hard coat.
With the way that low e glass windows are able to insulate heat and reflect UV and Infrared Rays from the sun, they are a great way to conserve energy. In an economy where energy costs are steadily rising, installing low e glass windows is home technology that has a very promising future.