In the previous post we began discussing how changes in custom window standards are affecting the manufacturers in Canada. We also touched on what it means to you as a consumer. Chances are, if you’ve read anything about replacement windows you will have heard about Energy Ratings and Climate Zones.

Most Canadian windows today are labeled with information that adheres to the international Energy Star standards rating. As window companies are beginning to adopt the new NAFS (North American Fenestration Standards), the changes are affecting Canadian Energy Star ratings as well.

Since the early 1990s ENERGY STAR is an international standard for energy efficient consumer products. Products carrying the Energy Star service mark symbol generally use 20–30% less energy than required by federal standards local. Although it originated in the United States, Canada and the European Union follow these standards for most consumer goods and building products.

There are several factors that are taken into account when determining whether vinyl windows adhere to Energy Star requirements.

U-Factor: U-Factor measures heat transfer. The lower the U-Factor, the slower the transfer of heat from a warm area to a cold area. This is the inverse of an R-value, which is commonly used with other construction materials to measure the insulation value. These values do not consider any heat that is gained from the sun through the window glass.

Solar Heat Gain Coefficient (SHGC): The solar heat gain coefficient is exactly what it sounds like – a measure of the solar heat gained through a pane of glass. It ranges from 0 to 100, with 100 having the most solar gain.

Energy Rating (ER): An energy rating balances a product’s U-Factor with its solar heat gain and airtightness. Ranging from 0 to 50, a higher energy rating indicates a more energy-efficient product.

Visible Transmittance (VT): Ranging from 0 to 100, visual transmittance measures the amount of visible light that can pass through the product. A higher value means more light will pass through.

Air tightness and other standards: Products are also tested in accordance with standards that measure airtightness, watertightness, and strength.

You can search performance numbers on all ENERGY STAR rated windows in Canada on this Natural Resources website.

Knowing what the different values represent can help you determine which windows are best for each of your rooms. It can also go a long way in determining what kind of add-ons or upgrades you may want for your windows. For example, if a window you are considering has a high U-Factor, you may want to invest in a gas fill to make it more efficient.

The incorporation of NAFS into the Canadian rating system also affected the existing Energy Star zones. The Energy Star zones were a common way to determine the minimum performance levels required in different regions in Canada for windows to qualify.

What climate zone are my windows in?

The table below demonstrates how zones will change as of February 1, 2015:

Changes to Energy Star climate zones in 2015 re-divided Canada into three zones instead of four. Most places in the country require windows compliant with Zone 2.
Changes to Energy Star climate zones in 2015 re-divided Canada into three zones instead of four. Most places in the country require windows compliant with Zone 2.

The changes in the zones don’t necessarily affect customers in most areas. For replacement windows in Alberta, Calgary windows are now in the same climate zone as Edmonton windows (Zone 2) and will require a minimum ER rating of 29 (previously 25).

Ultimately, the introduction of North American Fenestration Standards to the Canadian market will ensure that more information becomes available for customers. It also means testing of products will be more stringent to ensure the best quality in custom windows.

Learn more about replacement windows:
Find out how much a new window project should cost
Learn about the importance of correct window installation
See what features make an energy efficient window

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