Sun Management System
To understand how revolutionary the Sun Management System really is, you need to know a little bit about energy and heat as it applies to glass.
refers to the ability of a glass to resist heat flow from the sun's direct radiation, the short-wave energy that lies near visible light in the spectrum.
refers to the insulating value of the glass: its ability to resist the natural transfer of long-wave energy from the warmer to the cooler side by conductivity.
To evaluate how well a particular glass, or a combination of glass products in an I.G. unit, will actually perform, you need to consider the combined effect of both of these factors. Thermal control is measured by the U-value of the glass. The lower the U-value, the better the thermal control properties of the glass.
Solar control has traditionally been measured by the Shading Coefficient (SC).
In recent years, however, a more accurate measurement system has been developed. Called the Solar Heat Gain Coefficient (SHGC), it compares the total energy which passes through a glass or glass combination with the amount of solar energy shining on the glass.
For a single pane of 1/8" clear float glass, the SHGC would be 0.86, indicating that 86% of the solar energy striking the exterior of the glass enters the room by short-wave transmission and thermal conduction of the solar energy absorbed by the glass. The lower the SHGC, the less heat will be gained through a glass or combination of glass in an I.G. unit.