Glass Type:

Low-E glass

Low-E means high efficiency

Give your windows a comfortable coat

Low-emissivity glass (or low-E glass, for short) can make homes and buildings more comfortable and energy efficient. Microscopic coatings of precious metals such as silver have been applied to the glass, which then reflects the sun’s heat. At the same time, low-E glass allows an optimal amount of natural light through the window.

When multiple lites of glass are incorporated into insulating glass units (IGUs), creating a gap between the panes, IGUs insulate buildings and homes. Add low-E glass, such as ClimaGuard® and SunGuard® coatings, to the IGU, and it multiplies the insulating ability.

How Glass is Coated: The Technology Behind Low-E

You don’t have to see to believe

Energy from the sun consists of a spectrum of different kinds of light—infrared (heat energy), visible (light we can see) and UV (which fades objects such as furniture and art). Guardian scientists and researchers are continually developing new technologies that push energy efficiency, design flexibility and the well-being of occupants and contents to the next level. Each coating works to reflect both heat and UV light, while at the same time letting visible light shine through. These coatings are so thin that, if a sheet of paper represents the coating, the glass would be a seven-story building.

It's all about U

That’s U for U-factor, or how the industry measures glass thermal insulation. From Abu Dhabi to Winnipeg, and every climate in between, Guardian offers a wide variety of solutions to keep heated and cooled air inside.

How insulated glass works

Guardian Glass helps customers achieve optimal windows, regardless of the climate. To achieve excellent thermal insulation, several glass panes can be combined with at least one SunGuard or ClimaGuard low-E coating in an insulated glass unit. Two or more panes of the same size are then aligned, attached and separated by a hermetically sealed air space. That space is filled with especially high-thermal insulating gas, like argon. This enables the glass to meet two very different requirements – keeping conditioned air in and keeping extreme temperature out.


As one of the world’s largest glass coaters, Guardian offers low-E products through the SunGuard advanced architectural glass line. There you will find hundreds of options to meet your expectations for application, light transmission, colour and sustainability certification. For residential window manufacturers, ClimaGuard residential glass offers the very latest home window technology to meet ENERGY STAR® certification.


Residential glass that welcomes natural light and neutralizes the negative effects of the sun and frigid temperatures

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High-performance architectural glass that helps architects and designers Build With Light®

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