The Benefits of Low E Glass Windows

Of all the options and accessories to consider for your windows, the most important is really the most obvious, the glass. Accounting for up to 80% of a window’s real-estate, glass can make or break the overall performance of your system.

Durabuilt offers two high performance Low E Glass solutions, Sungate® 400 and Solarban® 60 with argon fill. Both offer performance enhancing benefits for year round comfort and savings:

Keeps the Heat Inside

Both Low E options will significantly reduce the amount of heat lost through your windows to help save on your heating energy costs. Lower U-values and higher R-values are an indication of greater performing windows.

Controls Solar Energy

The most unique attribute between our two Low E offerings is the Solar Heat Gain Coefficient (SHGC) or the amount of solar heat gain through the glass relative to the incident solar radiation (equal to 86% of the Shading Coefficient). Higher SHGC numbers provide natural energy in the winter to reduce heating costs, while lower numbers block heat gain in the summer to reduce cooling costs.

Clear Appearance

Visible Light Transmittance is the percentage of visible light that passes through a glass product. Durabuilt’s Low E glass solutions are highly transparent providing an aesthetically pleasing interior / exterior appearance similar to clear glass.

Fade Protection

Shading Coefficient is the ratio of total solar energy that passes through, relative to standard clear glass. Low E coatings block damaging ultraviolet (UV) rays to help protect your fabrics, furniture and carpets from fading.

Choosing the Right Low E Glass

Argon Gas is a colourless inert gas that is injected in the airspace of your insulating glass unit to improve energy efficiency. Argon is recommended with both Low E glass solutions and is a minimum requirement to meet Energy Star criteria.

Durabuilt Low E Glass Performance

Note: Tdw-ISO represents potential fading damage caused by both UV and visible light. It is considered by the U.S. Department of Energy and the International Standards Organization (ISO) to be a more accurate barometer of fade resistance than UV transmittance alone. All comparisons are center of glass based on an insulating unit containing 3/4″ insulating units; two 1/8″ (3mm) glass lights and a 1/2″ (12mm) air-filled space for the standard clear insulating glass and argon gas-filled space for the Sungate® 400 and Solarban 60 insulating glass. Actual glass performance may differ due to glass thickness, gas fill and glass to frame ratio. Solar Heat Gain Coefficient (SHGC) is a ratio of how much solar heat is transmitted through the glass compared to 1/8″ (3mm) thick clear glass. (Lower numbers mean less summer heat). Figures may vary due to manufacturing tolerances. All tabulated data are based on the National Fenestration Rating Council (NFRC) methodology, using the Lawrence Berkeley National Laboratory’s Window 5.2 software.

Durabuilt Overall Glass Performance

* Figures may vary due to manufacturing tolerances and controlled circumstances. The number in brackets indicates the position of the protective Low E coating; multiple numbers indicates a double application. All tabulated results are based on the National Fenestration Rating Council (NFRC) methodology, using the Lawrence Berkeley National Laboratory’s Window 4.1 software.

* Comparisons are based on centre of glass measurements against a clear 3/4″ insulating glass units; two 1/8″ (3mm) glass panes and a 1/2″ (12mm) air space. Actual glass performance may differ slightly due to glass thickness, gas fill, and glass to frame ratio. Clear glass allows 81% of visible light.

How Energy Star® Means Energy Efficiency

Energy Star is the international symbol for energy efficiency and an important consideration when building green and accessing government grants and incentive programs. Durabuilt is a proud volunteer partner of the Energy Star program and makes buying qualified windows and doors easy from the selection process, through to proof of purchase. Here’s how it works:  

1. Find Your Climate Zone


The Energy Star program divides the country into four climate zones based on annual average temperature. Zone 1 is the mildest and Zone 3 is the coldest.

Visit to find your town’s specific zone.

By installing energy efficient windows and doors in your home you can reduce energy costs by 7-12% or more*.
* Energy Star statistic based on controlled testing


2. Choose Windows & Doors that Qualify for that Zone

Once you determine your qualifying zone, you must select your windows, doors and performance options to meet that zone’s criteria. Low E with argon is a minimum requirement of the Energy Star program. Durabuilt windows can be configured to meet the most stringent Energy Star zones, especially our Casement Window Collections. To identify the qualifying zone of your windows:

a) Reference our Product Performance Charts

b) Visit

c) Check your Durabuilt quote / order summary

d) Ask your Durabuilt Sales Consultant for more information

3. Retain Your Labels Upon Installation

As part of the new Energy Star program Durabuilt has implemented a labeling system that clearly summarizes your window’s CSA and Energy Star information. This includes the zone for which the product qualifies – 1, 2, 3 – along with the relevant performance data including the U-Factor, Solar Heat Gain Coefficient and Energy Rating. It is important that you keep these labels for each product purchased as they can be used to qualify for government grants and incentives, as well as our warranty program.

Energy Star Requirements for Windows





Energy Efficiency: It All Adds Up

Durabuilt window and door systems are built to withstand extreme weather variation and meet the most stringent Energy Star requirements. Not just one component makes our windows and doors energy efficient, but rather all of them work together as a cohesive unit, making our products the best in the industry.

Window Performance

  1. High Performance PVC and Hybrid Frames
    Fully extruded multi-chamber profiles provide barriers for cool air and moisture to enter the home.
  2. Solar Control Low E Glass
    Low-E is a specialized window coating that acts as a virtual gate, permitting and deflecting solar energy.
  3. Triple Pane Glass
    Triple pane windows improve comfort, help save on energy costs and reduce noise in the home.
  4. All Foam Super Spacer ®
    Durabuilt uses the premium all foam, no-metal Super Spacer ® in all our windows.

Durabuilt Window Performance



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