Window Energy Efficiency: Solar Heat Gain and Visible Transmittance

2018-03-22T15:13:18+00:00

Conduction and Radiation of Thermal Energy In my last blog post, I wrote about the conduction and radiation of thermal energy through windows and the thermal transmittance value, called the U-Factor, that characterizes that heat transfer.  The U-factor is useful in evaluating window performance and making wise decisions when specifying components for a building, but it is only one piece of the puzzle.  The National Fenestration Research Council (NFRC) mandates a second value alongside U-factor in its certification process, called the Solar Heat Gain Coefficient (SHGC).  SHGC represents the ability of a window to resist heat gain from radiation, like the sunlight in Figure 1.  This is obviously a challenge, given that the entire point [...]

Window Energy Efficiency: Solar Heat Gain and Visible Transmittance 2018-03-22T15:13:18+00:00