Energy Star Windows Standards have recently updated and this of course affects how custom windows are manufactured in Canada. The following article will highlight these changes. Energy ratings and climate zones have been a topic of concern for those who are considering window replacement.

Keep in mind that most Canadian windows and doors companies label their products to show that they are in adherence with international Energy Star standards rating. However, many window companies are adapting to the new guidelines set by the NAFS (North American Fenestration Standards) which directly affect Canadian Energy Star

Changes to Energy Star Windows Standards

Energy Star has been the international standard for consumer products for energy efficient since the early 1990s. This includes Energy Star qualified windows. Any product that bears the service mark of Energy Star uses twenty to thirty percent less energy than those standards set forth by the local federal standards. Originally formulated in the United States of America, these standards are also followed by both the European Union and Canada for the majority of consumer products.

Following are the factors to keep in mind as to what determines Energy Star Windows:

Solar Heat Gain Coefficient (SHGC)

The Solar Heat Gain Coefficient is the measure of solar heat that is gained through a glass pane, which ranges from 0 to 100. 100 is the highest level of heat gain.


The U-Factor is the measurement of heat transfer. The slower the process of heat transferring from warm to a cold area, the lower the U-factor. The U Factor is the inverse of the R-value. The R-value is typically used to measure the insulation value. Neither of these two values take into factor any level of heat that is gained through the window glass via natural light.

Energy Rating (ER)

This is the balance of a product’s U-factor with its solar heat gain as well as the air-tightness. It ranges from to 50. The more energy efficient the window is, the higher the energy rating.

Visible Transmittance (VT)

Visual Transmittance is a measurement of the amount of visible light that is able to pass through the item in question. With values ranging from 0 to 100, the more light that the higher the value.

As well, energy star windows are tested in adherence to guidelines set forth to measure air tightness, strength and water tightness.

Being able to understand what these values represent will help homeowners decide which style and material of windows is best suited for each room of their homes. It can be extremely beneficial in determining what type of upgrades or custom features you can add to your window replacement. Per example, you might wish to add inert gas fills the windows with a high U-factor in order to enhance energy efficiency.

If you have any questions about the new standards for Energy Star Windows in Canada, call the experts at WeatherPro Windows and Doors. They can help you determine which windows are best for your needs.


About Weather Pro – Windows and doors company in Winnipeg, Regina, Saskatoon, Calgary, Edmonton.

Weather Pro Windows & Doors has years of industry experience and our goal is to use our expertise to help each and every client that approaches us, whether a first time buyer or a long-time homeowner, to find the perfect windows and doors that meet all their needs. We specialize in Replacement Windows, Vinyl Windows, Entry Doors, Exterior Doors and Patio Doors. Weather Pro Windows and Doors proudly serves the Winnipeg, Calgary, Edmonton, Regina & Saskatoon areas. Follow us on Facebook!!