Insulating glass

Control heat, stay comfortable

Guardian insulating glass offers dramatically improved thermal performance, regardless of the climate. Our insulating glass can transmit light beautifully, maintain ideal indoor temperatures and meet sustainability requirements. And our proprietary warm-edge spacers feature a stainless-steel design, reducing both condensation and U-values.

How insulating glass works

Insulating glass refers to two or more lites of glass sealed around the edges with an air space between, forming a double- or triple-pane unit. Commonly referred to as an “IG unit,” insulating glass is the most effective way to reduce air-to-air heat transfer through glazing. The air space may be filled with an inert gas such as Argon to further reduce heat transfer and increase total comfort. When used in conjunction with low-E and/or reflective glass coatings, IG units become effective in conserving energy and complying with energy codes.

Insulating coatings

Guardian coatings provide substantial improvements to insulated glass units. Compared to uncoated insulating glass, SunGuard® coatings offer up to 50 percent in U-values and solar heat gain coefficients. Explore Guardian insulated glass coating options below, or contact your Guardian Glass sales representative for more information.


To see all of the low-E coatings that Guardian Glass has to offer for residential glass, explore the ClimaGuard® residential glass product line:

Guardian Glass - ClimaGuard - 80/70 - man and daughter playing

ClimaGuard 80/70

ENERGY STAR® Northern Zone

Selectively lets visible light in to brighten and warm northern homes naturally, and provides insulation to stop heat from escaping

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Guardian Glass - ClimaGuard - 72/57 - man listing to music, snowy landscape and mountain outside window

ClimaGuard 72/57

ENERGY STAR® Northern and North-Central Zones

Provides ample light, solar heat gain and retains heat indoors in climates with cold winters

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Guardian Glass - ClimaGuard - 53/23 - photo of young African America woman reading on sofa with glass of juice

ClimaGuard 53/23

South-Central and Southern ENERGY STAR® Zones

Cools homes in warm, southern climates with triple silver protection to lower solar heat gain and U-value

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Guardian Glass - ClimaGuard - IS-20 - a group of friends playing a game

ClimaGuard IS-20


Enhances performance by lowering U-value of standard low-E windows to help meet energy codes

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To see all of the low-E coatings that Guardian Glass has to offer for residential glass, explore the SunGuard® coated glass product line:

Guardian Glass SunGuard - Hearst Corporation building


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

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Insulating glass for appliances

Guardian Glass offers IG units and coatings to help commercial refrigerators meet ENERGY STAR®, EPA and EISA compliance.

Refrigerators in the dairy section of a supermarket that use Guardian ThermaGuard glass


A range of low-E, anti-reflective (AR) and hybrid products that set new standards for performance and aesthetics in refrigeration