Whole Product SHGC Calculations

Software/Versions Affected:

The ISO 15099 formula for the frame Solar Heat Gain Coefficient (SHGC) specifies that the surface area (Asurf) should be the outdoor wetted surface, while the frame area (Af) should be the indoor projected surface area. By default, if there are no exterior U-factor tags, THERM passes the inside wetted length to WINDOW5 for the SHGC calculation. In order for THERM to pass the exterior wetted surface length, tag the exterior frame boundary conditions with the U-factor tag of "SHGC Exterior". In the latest installation of THERM, this tag is in the default U-factor tag library, but if it is not there, you can be added to the library.