How To Compare Replacement Windows?

If you are looking to get the most comfort and efficiency out of your window replacement, there are several standards that the products you buy must adhere to. There are always homeowners looking to do the cheapest and quickest job. But you will find that when it comes to windows and doors, the difference in price often means a difference in quality.

So how do you know if a window performs well and will last as long as possible?

Be sure to check out how different Calgary window suppliers’ products compare:
Casement Windows In Calgary
Slider Windows in Calgary
Awning Windows in Calgary

There are two main factors to consider when picking and comparing windows:

1. All quality windows in Canada adhere to the CSA – A440 standard.
2. All quality windows are ENERGY STAR rated.

Because both the Canadian Standards Association (CSA) and Energy Star rely on similar criteria for evaluating windows, usually if a window is good enough to qualify for one standard, it also qualifies for the other. Very rarely will you see a window manufacturer that sells ENERGY STAR qualified windows, that don’t meet the CSA standard.

The best thing for homeowners is that this information is publicly available online:

You can search for CSA compliant window companies here.

You can check ENERGY STAR qualified window companies in Canada here.

Understanding CSA standards for comparing windows

As a Canadian window consumer, the windows you purchase should adhere to the CSA – A440 standard. The Canadian Standards association has laid out specific guidelines for window performance in these categories:

1. positive design pressure, where applicable;
2. negative design pressure, where applicable;
3. water penetration test pressure; and
4. air infiltration and exfiltration level.

Sometimes you will see windows with ABC ratings. For example, a window that is rated A3, B6, C4 is more efficient and better performing than a window that is rated A3, B6, C2.

One way to recognize whether windows are CSA certified is that they have a CSA logo on the glazing and come with a CSA label that outlines the window’s performance metrics in the four categories mentioned above. But if you look at the picture below, you’ll see that the ratings provided on the label, aren’t the same as the ones used by CSA.

While the CSA-A440 is the minimum standard all windows installed in Canada should comply to, different windows have their own unique Energy Ratings (ER) based on several measurements of performance. Energy Ratings are a more simplified and harmonized way to understand and compare window performance.

Understanding Energy Ratings when comparing windows

A window’s ER rating is calculated on three factors: solar heat gains, heat loss through frames, spacers and glass, and air leakage heat loss. ER ratings rank between 0-50, the higher the rating, the more efficient the window.

The ER number is a balance between heat loss ratings (U-Factor) and solar heat gains through the window (SHGC).

U-Factor is a measure of how much heat a window system loses. Note the use of the word system here. Traditionally window performance was often judged by the R-value of the materials used, but modern windows often use different materials with different R-values, so it is not accurate to measure these values in relation the window as a whole. The lower the U-Value, the less heat is lost through the whole window. Some of the best thermal windows on the market achieve a U-Value of 1 or slightly lower.