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".