It is the percentage of the total solar energy entering the glass. Lower solar energy total transmittance value means better solar control. Solar energy is a phenomenon that we want to avoid in hot weather and utilise in cold weather. Therefore, it may be logical to use our choice in favour of glass that passes more light and heat on the northern facades where there will be less illumination but less heating. However, in hot climates, solar energy will increase cooling costs, so we want to avoid it as much as possible. In cold climates, high SHGC is preferred to maximise the use of passive solar energy (>0.55). In hot climates, it is recommended to be less than 0.4.
