Shading Coefficient (SC)
An alternative measure of the heat gain through glass from solar radiation.
Specifically, the shading coefficient is the ratio between the solar heat gain for a particular type of glass and that of double-strength clear glass.
A lower shading coefficient indicates lower solar heat gain. For reference, 1/8" (3.1 mm) clear glass has a value of 1.00. (SC is an older term being replaced by the SHGC).