Heat absorbed through direct transmission through glazing (primary transmittance). Energy is also absorbed by the glazing and subsequently transferred inwards by convection and radiation (secondary tr [..]

Solar gain (also known as solar heat gain or passive solar gain) refers to the increase in temperature (heat gain) in a space, object or structure that results from solar radiation. The amount of sola [..]

Solar gain (known also as solar heat gain or passive solar gain) refers to the temperature increase in a space, object, or structure caused by solar radiation. The amount of solar gain increases with the strength of the Sun, and with the ability of any intervening material to transmit or resist the radiation.

Objects struck by Sunlight absorb the short-wave radiation from the light and re-radiate the heat at longer infrared wavelengths. Where there is a material or substance between the Sun and the objects struck that is more transparent to the shorter wavelengths than the longer, then when the Sun is shining the net result is an increase in temperature - hence solar gain.