Glassmaster Logo Glassmaster
Window Films

Glossary of Technical Terms

Clear explanations to help you find the best film for your application. Please feel free to call us at 800-919-5044 if you have questions.

Click on a term below to learn more
Visible Light Transmitted

It is the ratio of visible solar energy (380 - 750nm) that passes through the glazing system to the total visible light falling on the system.

Visible Light Reflectance

It is the total percentage of visible light to be reflected by a glazing system that can be seen visually.

Total Solar Energy Transmitted

It is the ratio of the total solar energy passing through a glazing system to the amount of total solar energy falling on that glazing system.

Total Solar Energy Reflected

This is the ratio of the amount of the total solar energy directly reflected by the glazing system to the amount of total solar energy falling on that glazing system.

Total Solar Energy Absorbed

The ratio of the amount of total solar energy directly absorbed by the glazing system to the amount of total solar energy falling on that glazing system.

Ultraviolet Light Transmitted

This is the ratio of solar energy (wavelength of 300 - 380nm) that is transmitted by a glazing system to the total solar Ultraviolet energy falling on the glazing system. Note: UV energy is not visible to human eye and is mainly responsible for the degradation and de-coloration of organic matter, upholsteries, colors etc.

Total Solar Energy

A sum of energy transmitted, reflected and absorbed by the glazing system is known as total solar energy (100%).

Total Energy Rejected

It is the percentage of incident solar energy rejected by a glazing system equal to the solar reflectance + a part of solar absorption which is re-radiated outward.

'U' Factor

U Factor is a measure of the rate of heat conductivity of a glazing system, and it is independent of solar radiation. When multiplied by the difference between indoor and outdoor temperature in Fahrenheit, it gives the amount of heat in BTUs/hour/square foot of glazing. Note that the greater the temperature difference, the greater the U Factor, so it is important to use the U Factors closely representing your conditions.

Shading Coefficient

The Shading Coefficient is the ratio of the solar heat gain through a given glazing system to that of a standard plane glass (1/8 inch or 3mm thickness) under the same test condition. Lower the Shading Coefficient number betters the sun control capability.