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How Low Emissivity Glass Works


Many windows now feature low emissivity or Low-E coatings. Our replacement windows have this as a feature in our glass packages. In this blog, Renewal by Andersen® of San Francisco shares an in-depth look at Low-E glass and how it can benefit you.

How Low Emissivity Glass Works

Invisible Light

To understand how low emissivity coatings work, we’ll first explain what it does: it protects your home from sunlight, or more precisely, invisible rays. Sunlight is composed of bands of radiation, which can be roughly grouped into two. There’s visible light that we perceive as a bright light, which is actually composed of several bands of colors that are visible individually when seen through prisms or as rainbows.

Invisible light, on the other hand, consists of a larger fraction of sunlight and includes infrared and ultraviolet (UV) rays, among others. Infrared rays are what make sunlight hot while UV rays have a bleaching effect that causes fading on colored fabrics and furniture.

Low Emissivity Coatings

Tints and reflective film were the accepted solution for a long time. While they did filter sunlight, they also made indoor spaces dark. They also made the windows more like one-way mirrors, which, at certain angles, could be obstructive or even dangerous for neighbors. Low emissivity coatings are different in that they allow visible light through while selectively blocking everything else. When applied to window replacement units, these coatings allow as much natural light as clear glass does while blocking unwanted UV and infrared rays.

High-Performance™ Low-E4® Glass

Renewal by Andersen replacement windows feature High-Performance™ Low-E4® glass. It combines insulation from radiant heat with its dual-pane design, insulated spacers and Fibrex® material frames with the Low-E4 coatings that effectively block UV and infrared rays. With several options like our High-Performance Low-E4 Sun glass that tempers harsh sunlight, you can enjoy the benefits of natural lighting without its unwanted effects.

To learn more about low emissivity glass or our windows replacement services, call Renewal by Andersen of San Francisco today at (510) 263-3210. You can also fill out our contact form to schedule a free in-home consultation. We serve San Francisco and surrounding areas.


"I wished to have this done long time ago, had I known the benefits of these products provided by Renewal by Andersen"

June 26

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