Sunrooms By Brady Sunrooms By Brady

June 7, 2012

What does low e mean and how does it make glass better?

Filed under: Glass — Tags: , , , , , , , — Sunrooms by Brady @ 2:09 pm

Sometimes it can be difficult to keep up with all the specific terms and phrases if you aren’t involved in the industry personally. That’s why we want to give you the chance to learn about the products we use and why! Today we explain low e glass and its benefits.

Windows are obviously a very important part of sunrooms!“Low e” is short for “low emissivity” or if you want to get even more accurate, “low thermal emissivity”. Reflectivity is inversely related to emissivity. All materials have a value for reflectivity and emissivity. For instance, a red brick has an emissivity of 0.9 and a reflectance of 0.1. Glass is naturally a high emissivity material with a low reflectance value (when viewed at a 90 degree angle). This means most wavelengths of light (energy) pass through it easily with very little being reflected. Visible and near visible light is made up of many colors of light, ranging from Infrared to Ultraviolet. When an object is heated it radiates infrared light. This light is not visible to the human eye, but it is the form of energy that causes the most heat loss and gain through glass. Untreated glass allows infrared to pass through, so in the summer when you don’t want a room to be heated by the sun, regular glass lets this happen. In the winter, when you don’t want the heat from your furnace to go out through the windows, it does through regular glass.

Windows can be made to hold more heat inside the house by applying a low e coating, which is usually a layer of metal or metallic oxide that is so thin it appears invisible. The metals used are selected because one of their properties is to reflect infrared light. Since infrared light is invisible to the human eye, blocking it from passing through the glass does not change the colors we see in the house or through the glass.

How does the low e coating help me? Unlike the previous description of what happens to regular glass; with low e coated glass, in the summer when you want to reduce some of the heat gain from the sun, the low e coating blocks the infrared light from getting into the house and heating it up. In the winter, when you are heating inside, the low e coating blocks the infrared light from going through the window thereby keeping the house warmer and using less heating fuel.

A glass room without any low e coating or tint in the glass would get unbearably hot on just about any sunny winter day. Use of infrared blocking low e coatings is a strategy used to provide “just enough” solar heating, allowing other wavelengths of light to provide the warmth you desire without overheating.

Brady-Built Sunrooms has chosen a low e coating for its glass that provides superior infrared light control and when used in conjunction with our solar screens in the summer months, provides year round comfort and much better performance than any of our competitors glass alone.

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    Pingback by What does low e mean and how does it make glass better? « The Sunroom News — June 8, 2012 @ 3:16 am

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