What are U-Value, Solar Heat Gain Coefficient and Visual Transmission?
A. U-Value is the rate of heat flow-value through a building component, from room air to outside air. The lower the U-factor, the better the value of the component. Solar heat gain coefficient is a rating measuring a windows ability to transmit solar heat. It measures both the solar radiation which is directly transmitted, as well as the solar radiation absorbed by the glass and subsequently transmitted. The lower a units solar heat gain coefficient, the less solar heat it trans-mits, and the greater is its shading ability. Visual Transmittance is the rating that expresses the potential amount of visible light transmitted through a window or door.
