Blog > Category Post > Posted: 2017-Jul-25, Updated: 2020-Sep-21

Energy Star product specifications comparisons

When making decisions on who to buy your windows from, the comparative information is easy to find. However, it can be a little overwhelming to decipher.

If window energy efficiency is important to you, then your best resource is the Natural Resources Canada, Energy Star Program. Visit their website for up-to-date information on Energy Star approved window products and specific product results that can be used for comparison.

Although there are almost 100,000 window models on the list, you can search specific manufacturers and window models to find efficiency rating data.

Even though all the technical information you could need is readily available, the specifications can be confusing and to make matters worse alternative rating units are sometimes used making it even more difficult to interpret the results.

Using the available product specifications spreadsheet we created a sample comparison sheet of some, but not all local products that are available in the Ottawa area. We chose single casement windows for our example.

Our local sampling

For the sake of clarity and understanding, our trimmed-down example was created from the 2017 Canadian Energy Star Most efficient window supplier list which was downloaded from the Natural Resources Canada website:

1. We filtered out:

  • Many of the manufacturers that really don’t market themselves in the Ottawa area
  • Non-vinyl single casement windows
  • Windows that did not meet zone 1, 2 & 3 ratings
  • Excluded infill. Air Leakage L/s*m2 & Exfil. Air Leakage L/s*m2

2. Sorted the spreadsheet for most efficient products/brand:

  • Energy rating
  • Solar heat gain
  • U-factor (Btu/h-ft2 F) & U-factor (W/m2 K)
  • Visible transmittance (VT)

3. Added green for the top 2 performers for each rating

The results

Filtering produced the best rankings for each manufacturer from the manufacturer’s list. The spreadsheet indicates the best ratings for each product shown.

Create and edit your own list


If you really want to get the best energy efficiency, quality, and affordability in your window purchase, then you need to do your homework.

Most window replacement companies will include the window ratings for their window in their quotes. If they don’t, you should ask for them. Keep in mind you want to compare apples to apples and be aware, that with so many variations of window products out there, it’s easy to misread the specifications - double-check your results.

Over time, picking the most energy-efficient windows will save you money and maximise the comfort inside your home.


The intention of this post was not to show bias to any particular brand. The sample findings were put together for demonstrative purposes only. To get a better understanding of how products compare, be sure to look at the model numbers and specifications being supplied by the companies you are getting quotes from.

If you would like to know more, give us a call or send us a request for more information. We’d be happy to address all of your questions or concerns.

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