- Visible Light Reflected: The percent of total visible light to be reflected by a glazing system. Test method – ASTM E 903-82.
- VLT: Visible Light Transmitted or VLT is the percent of total visible light that passes through the glass.
- Total Solar Energy Absorbed: The percent of total energy to be absorbed by a glazing system. Solar absorbency is that portion of total solar energy neither transmitted nor reflected on glass. Test method – ASTM E 903-82.
- Emissivity: The ability of surface to absorb heat and to reflect it. The lower the emissivity, the less room heat is absorbed – the more heat is reflected back into the room.
- Shading Coefficient: The ratio of solar heat gain through a given glazing system to the solar heat gain under the same conditions for clear, unshaded double strength window glass (DSA). The shading coefficient defines the sun control capability of the glazing system.
- Ultra Violet (UV) Block: The percent of Ultra Violet radiation to be passed through a glazing system. Test method – ASTM D1003.
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Solar Heat Gain Coefficient: The total amount of solar energy that goes to the inside of the building by reflection and by absorption.
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Total Solar Energy Rejected: The percent of solar energy rejected by a glazing system equals solar reflectance plus the part of solar absorption which is reradiated outward.
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Total Solar Energy Reflected: The percent of total solar energy (300-2500 nanometers) to be reflected by a glazing system. Test method – ASTM E 903-82.
- Total Solar Energy Transmitted: The percent of total solar energy to be passed through a glazing system. Test method – ASTM E 903-82.
- U-Factor: The overall heat transfer coefficient of the glazing system, U -Factor is a measure of the heat transfer that occurs through the glazing system, and its outer and inner surfaces. The overall coefficient of heat transfer equals the reciprocal of R value.
