ISO has published a standard that specifies a method to measure the solar heat gain coefficient (SHGC) of complete doors and windows.
ISO 19467:2017 is titled “Thermal Performance of Windows and Doors – Determination of solar heat gain coefficient using solar simulator.” According to the document, it is “designed to provide solar heat gain coefficient values by standardized measurement method and to enable a fair comparison of different products.”
It specifies standardized apparatus and criteria, and the SHGC-measuring apparatus applied in it includes the solar simulator, climatic chamber and metering box.
The document applies to doors and windows with various types of glazing, including systems that are single- or multi-glazed; with or without low-E coatings; and with spaces filled with air or gases.
It also applies to doors and windows with opaque panels, as well as various types of frames, shading devices and solar fenestration systems – including building-integrated photovoltaics or building-integrated solar thermal collectors.
ISO 19467:2017 doesn’t include shading effects of building elements, heat transfer caused by air leakage between indoors and outdoors, or ventilation of air spaces in double and coupled windows. It also doesn’t include “thermal bridge effects at the rebate or joint between the window or door frame and the rest of the building envelope,” according to the document.