Solar heat gain coefficients (SHGC) represent the amount of solar radiation that enters a building through windows and other fenestration. SHGC values range from 0 to 1, with lower values indicating less solar heat gain. The SHGC value depends on factors such as the type of glazing, frame material, and shading devices. Accurate estimation of SHGC values is crucial to ensure that the cooling system is sized correctly and to optimize energy efficiency. For example, a building with low-E glazing and external shading devices will have a lower SHGC value than one with single-pane glazing and no shading devices.