Step 7

Do I Need The Highest Performance Level?

Just like energy efficiency, the window’s overall performance is also essential to making the best decision. The following three factors must be considered when determining a window’s strength and efficiency:

  • Wind resistance
  • Water tightness
  • Air tightness

To know the overall performance of a window, ask to see its North American Fenestration Standard (NAFS) results. This will tell you the performance grade (PG) of a window obtained during tests performed in accordance with the fenestration requirements imposed by the National Building Code.

Before purchasing windows in Canada, be sure to validate the minimum performance grade (PG) required by your environment (region, height of the product, type of terrain, etc.). Determine your minimum PG with the Building Code Fenestration Performance Calculator.


The perfect reminder tool to help you buy with confidence!

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