Berkeley Lab WINDOW
Calculates performance of window and shading systems. It can be used to design and develop new products, teach about heat transfer through windows, and help develop building energy codes. It calculates total window thermal performance indices (i.e. U-values, solar heat gain coefficients, shading coefficients, and visible transmittances) for glazing and framing, as well as thermal and solar optical effects of a wide range of interior, between glass, and exterior shading systems.