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.


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.