What standard must new windows meet in Ontario (NAFS)?
Windows, exterior doors and skylights in Part 9 buildings must comply with NAFS, the North American Fenestration Standard (AAMA/WDMA/CSA 101/I.S.2/A440), plus the Canadian Supplement CSA A440S1, with performance grades matched to local climate.
Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.
NAFS labels give each product a Performance Class (R, LC, CW, AW) and a Performance Grade; the Canadian Supplement translates your project's location and terrain into minimum required grades, especially the water penetration rating. A window fine for a sheltered Toronto infill may fail requirements on an exposed Lake Huron shoreline. Ask suppliers for the NAFS label data and keep it for the building department. Energy performance (U-value, Energy Star zones) is a separate requirement under SB-12, not part of NAFS itself.
New windows and glass doors must be factory-tested to a North American standard called NAFS, which rates them for wind, rain and air leakage. Windier or more exposed locations need higher-rated products, so the label matters.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.