Is it better to have the coating on the #2 or #3 surface of an insulating glass unit?
A8 – The answer to this question is really dependent on the specific design conditions of your application. The light transmittance and U-Value of the unit will be the same whether the coating is on the #2 or #3 surface; however, the Solar Heat Gain Coefficient will be lower when the coating is on the #2 surface. In general, if you are concerned about reducing solar heat gain (typically in a cooling climate), then using the coating on the #2 surface would best meet the requirement. On the other hand, if you are interested in utilizing passive solar heat gain (typically in a heating climate) then using the coating on the #3 surface would best meet the requirement.
