A rating, which is now generally replacing shading coefficient, measuring a window's 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 unit's solar heat gain coefficient, the less solar heat it t [..]

The ratio of the solar heat gain entering the space area through the fenestration product to the incident solar radiation. Solar heat gain includes directly transmitted solar heat and absorbed solar r [..]

a measure of how well a window blocks heat gain from solar radiation. The rating ranges from 0 to 1, with lower numbers indicating better heat resistance.

Solar heat gain coefficient (SHGC) is the glazing's effectiveness in rejecting solar heat gain. SHGC is part of a system for rating window performance used by the National Fenestration Rating Cou [..]

A measurement of a window’s ability to transmit solar energy. The lower a window’s SHGC the less solar energy it transmits. Soft-coat glass:

The percentage of heat gained from both direct sunlight and absorbed heat. The smaller the number, the greater the ability to reduce solar heat gain.

Is the US equivalent of G-value. The only difference between the numbers is that SHGC uses an air mass of 1.5 and the g value uses an air mass of 1.0

(SHGC) The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.

  The percentage of solar heat that is absorbed vs. reflected when it contacts a window.

The measure of how much solar heat gain energy a glass combination will allow to pass through. A higher SHGC allows more potential solar heat gain than a lower SHGC (see SunStop.)