The Ontario Building Code | Windows and Sliding Glass Doors
12.3.1.2. windows and Sliding glass doors
(1) The energy rating and the overall coefficient of heat transfer required for windows and sliding glass doors shall be determined in conformance with,
(a) CAN/CSA-A440.2, "Fenestration Energy Performance", or
(b) NFRC 100, "Procedure for Determining Fenestration Product U-factors" and NFRC 200, "Procedure for Determining Fenestration Product Solar Heat Gain Coefficient and Visible Transmittance at Normal Incidence".
In Plain Language
The energy rating and overall coefficient of heat transfer required for windows and sliding glass doors must be determined per the referenced CAN/CSA-A440.2 or NFRC 100 standards, as set out in this article, ensuring consistent energy performance measurement.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.