Insulating Glass

Give Yourself the Gift of Free Energy Savings

Insulated glass delivers what every homeowner wants: Lower cooling bills when it’s hot outside and lower heating bills when it’s cold. Insulated glass is the ideal choice for our northern climate. It combines the highest solar heat gain (free energy) with good insulating properties, which is why it produces the best year round energy savings. Not all low-e’s are the same – while most low-e glasses have similar performance from an insulating standpoint, they perform quite differently from a solar heat gain standpoint. Solar heat gain is quite simply the amount of free energy we can get from the sun.

Insulating glass at a glance

  • Helps windows meet strict ENERGY STAR’ guidelines.
  • Brightens homes with 62% of the sun’s visible light.
  • Attractive neutral appearance with a color-matching heat-treatable product.
  • Solar Heat Gain Coefficient = 0.266 / UV Transmission = 8%
Super Spacer Brochure
Energy Andvantage Brochure

The power of triple-silver

The naked eye can’t see it, but there are three layers of silver within the coating of the glass. Many residential windows have just one or two layers. In insulated glass, this third layer of silver helps the window block more of the sun’s heat on hot summer days and retain more of a home’s warmth during cold winter nights. It also reduces the amount of harmful UV rays that penetrate window glass, down to only 8% of UV generated by the sun, extending the life of woodwork, carpets and furnishings.

Insulating glass means more light with less heat

The numbers tell the story. “62” indicates that 62% of the sun’s visible light shines through the glass. “27” indicates that only 27% of the sun’s heat makes its way through (the other 73% is blocked). That means plenty of sunshine can add beauty to a home without adding too much heat.

And with a U-factor of 0.24 insulated glass can improve window insulation and help save on heating bills. Better yet, combine 62/27 with insulated glass IS coatings on the #4 surface and windows can achieve U-factors below 0.20.

Windows are designed to help control your environment and maintain comfort. New technologies in low-E coatings and spacers are available that help regulate the transfer of heat through window glass.

triple glass
Visible Light U-Factor

Double Glazed

Trans Reflect In Reflect Out UV Trans SHGC 1/2″ Agron Gap Air 5/16″ Agron Gap Air
62/27 62% 11% 12% 8% 0.278 0.245 0.292 n/a n/a
62/27 + IS-20 60% 12% 13% 8% 0.271 0.203 0.238 n/a n/a

Double glazed: 3.0mm Clr: Air and 90% Argon/10% Air Filled Units. Primary low e-coatings are on the #2 surface; Insulated glass IS coatings are on the #4 surface; Performance data calculated for center-of-glass-only (no spacer or framing) using LBNL Window 6, IGDB v.47.0.

climate map

ENERGY STAR® criteria, building and energy codes, and “green” incentives play increasingly large roles in the residential window business. We understand your need to stay one step ahead to maintain your long-term business success. You can trust that Guardian is on top of the latest state and local window-building codes, ENERGY STAR® programs as well as industry trends. Think of us as your residential energy efficiency expert.

ENERGY STAR® Climate Zones

  • Zone 1 (Canada) – Triple-Glazed or High SHGC Double-Glazed

  • Zone 2 (Canada) – Double-Glazed w/ 4th Surface Coating or High SHGC Double-Glazed

  • Zone 3 (Canada) – Double-Glazed w/ 4th Surface Coating or High SHGC Double-Glazed

  • Northern (United States) – Double-Glazed w/ 4th Surface Coating or High SHGC Double-Glazed

  • North – Central (United States) – Low SHGC Double-Glazed

  • South-Central (United States) – Low SHGC Double-Glazed

  • Southern (United States) – Low SHGC Double-Glazed

decrease energy cost

Low-e glass helps stop heat from escaping homes. Decreasing energy costs.

solar heat glass

Low-e glass allows passive solar heat gain to warm your home. Decreasing energy costs.

How it works…

Solar heat gain is free energy from the sun. It comes in through your window glass and provides free heat. Ordinary clear glass allows room heat to escape, eventually costing you money on your energy bills. Insulated glass is a high performance, energy-efficient glass made with a coating that is designed for top performance in our northern climate, which is why it can rate highest on the Canadian Energy Rating.

Insulated glass allows the sun’s energy to warm your home in the winter. In cold weather conditions, room heat flows out toward the cold. As a result, your furnace is working overtime – increasing your utility costs. The special low-e coating helps block that transfer of heat, ultimately saving you money.

High Solar Heat Gain vs. Low Solar Heat Gain

High solar heat gain glass is designed for optimal performance in our northern or heating dominated climate because it allows free solar energy or heat to enter your home much like a solar collector. Room heat is heat generated inside a building which is at or near room temperature. Normal clear glass wastes energy by allowing more of your room heat to escape in the winter. Insulating glass is designed for optimal performance in our northern or heating dominated climate because it allows free solar energy, or free heat to enter your home and keep it inside.

Insulating glass benefits

Built in Temperature Control.
Because insulating glass helps keep the inside glass warmer, you can enjoy a more comfortable humidity level. This greatly reduces condensation and fogging on your windows, so you don’t have to wipe off windows and sills, or worry about moisture damaging the interior of your home.

Give Back to the Environment.
Insulating glass is environmentally friendly because it uses clean, abundant, free solar energy. With today’s energy prices, the energy cost benefits range from 6% to 27% with low-e glazed windows compared to conventional windows.

Increased Comfort.
Insulating glass warms interior glass surfaces, so you don’t need to bundle up inside or rearrange the furniture in the winter to avoid cold spots.

Graph showing total annual heating and cooling costs computed for North American locations. (US locations in US $, Canadian locations in Can $)

energy saving Canada