Low-E glass is a type of glass that has been coated with a thin layer of metal or metallic oxide. This coating reflects infrared radiation, which helps to keep heat in during the winter and out during the summer. Low-E glass is a popular choice for windows and doors, as it can help to improve the energy efficiency of a home or building.

What is Low-E Glass?

Low E Glass IllustrationThe term “Low-E” stands for “low emissivity.” Emissivity is a measure of how well a material reflects or emits heat. A material with a low emissivity reflects heat well, while a material with a high emissivity emits heat well.

The coating on low-E glass is typically made of silver, tin oxide, or zinc oxide. These metals or oxides have a low emissivity, which means that they reflect infrared radiation well. This helps to keep heat in during the winter and out during the summer.

How Does Low-E Glass Work?

When sunlight hits a window, some of the light is absorbed by the glass and some of the light is reflected. The absorbed light is converted into heat, which can warm up the interior of a home or building. The absorbed light passes through the glass and into the interior.

Low-E glass reflects more infrared radiation from sunlight, which helps to keep heat out during the summer. This can help to reduce the amount of energy that is needed to cool a home or building.  In the winter, the heat from indoors also reflects back into the home or building to retain heat and reduce heating costs.

Can Low-E Glass Be Tempered?

Yes! Tempering low-E glass can be done to help the glass be safer should it break.  In fact, almost all building codes require insulated glass used in windows and doors to be tempered.  Clearlight’s large Glaston tempering furnace has convection capability, a key functionality to promote even heating across the glass which keeps it flatter following tempering.  As you can imagine, heating glass where one side reflects heat is challenging.  Convection ability significantly improves tempering outcomes by circulating the hot air throughout the oven chamber.

What Makes Low-E Glass Worth the Extra Expense?

Low-E glass can help to save energy, which can save you money on your heating and cooling bills. In addition, low-E glass can help to improve the comfort of your home or building by reducing the amount of temperature fluctuation.

How Much More Does Low-E Glass Cost than Comparative Alternatives?

The cost of low-E glass varies depending on the type of glass and the thickness of the coating. However, low-E glass typically costs about 20%-30% more than standard glass.


Low-E glass is a type of glass that can help to improve the energy efficiency and comfort of your home or building. If you are considering replacing your windows or doors, low-E glass is a good option to consider.

Here are some additional benefits of low-E glass:

  • It can help to reduce glare and improve visibility.
  • It can help to protect your furniture and belongings from the sun’s harmful UV rays.
  • It can help to extend the life of your windows and doors.

If you are interested in learning more about low-E glass, please reach out to us. We would be happy to answer any questions you have and help you find the right low-E glass solution for your needs.

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