What is a U-Factor? The rate of heat loss is indicated in terms of the U-Factor. The lower the U-factor, the greater a window’s resistance is to heat flow and the better its insulating properties.
What is a Solar Heat Gain Coefficient? The Solar Heat Gain Coefficient (SHGC) is the fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed and subsequently released inward. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.