The following provides a glossary of terms often used when discussing Flat Glass films:
Visible Light Transmission Visible Light Transmission (VLT) is the percentage of solar visible light (daylight) that passes through a glazing system.
Solar Energy Rejected Solar Energy Rejected (TSER) is the percentage of total solar energy (heat) that is rejected away from a glazing system. This equals solar heat reflectance plus the amount of solar heat absorbed that is then re-radiated outwards.
UV Light Protection UV Light Reduction is the percentage of Ultraviolet Rays that is rejected away from a glazing system.
Exterior Reflectance Exterior Reflectance is the percentage of reflectivity (mirror effect) that occurs on the outside of a glazing system.
Interior Reflectance Interior Reflectance is the percentage of reflectivity (mirror effect) that occurs on the inside of a glazing system.
Solar Absorption Solar Absorption (TSA) is the percentage of total solar heat that is neither transmitted through nor rejected away from a glazing system (i.e. the percentage of total solar heat absorbed by the glazing system).
Solar Reflectance Solar Reflectance (TSR) is the percentage of solar heat that is reflected away from a glazing system.
Solar Transmission Solar Transmission (TST) is the percentage of solar heat that passes through a glazing system.
Shading Coefficient Shading Coefficient (SC) is the ratio of solar heat gain passing through a glazing system to the solar heat gain that occurs under the same conditions if the window were made of clear, un-shaded double strength window glass (lower SC equals better solar shading performance).
Solar Heat Gain Coefficient Solar Heat Gain Coefficient (SHGC) is the percentage of total solar heat that enters a glazing system. This includes heat directly transmitted as well as heat that is absorbed by the glass and then transmitted inwards (lower SHGC means less heat transfer from the exterior to the exterior).
U Factor U Factor or (U Value) is a measurement of solar heat transfer due to outdoor/indoor temperature differences. It's the amount of heat passing through one square foot of glass in one hour for each 1 degree Fahrenheit temperature difference between the indoor and outdoor air (the lower the U Value, the less solar heat passes through a window).