Total Solar Energy Rejected (TSER)
TESR is an important measurement of the window films ability to reject solar heat in the form of Visual Light (44% of heat) and Infrared Light (53% of heat). Clear glass transmits very high levels of both Visual and Infrared Light. Measured by the ratio of solar energy transmitted directly through the glass. Expressed as a percentage, it does not include heat re-radiated from energy absorbed in the glass.
Infra Red Rejection (IR)
There is a great deal of work being done in the industry with IR Films, sometimes known as Spectrally Selective films. As the Infra Red Light Band carries 55% of solar energy, Films targeting that specific Light Bands and becoming readily available . Some very light VLT films can have high heat rejection. The IR rejection is a percentage of the IR Solar Energy rejected by the film, however it is important to consider that it is the percentage of the 55% of the total Solar Energy carried in the Infra Red Light Band.
(SIRR) Selective Infra Red Rejection is the percentage of IR radiation that is not directly transmitted through a glazing system.
(IRER) Infra Red Energy Rejection is the percentage of Near Infrared Energy Rejection as measured between 780-2500nm.
Visual Light Transmittance (VLT)
The percentage of light (380nm -800nm) that is transmitted through the window film when installed. Clear glass generally has a VLT of about 89% prior to installing any window film.
Shading Coefficient (SC)
Shading Coefficient is the measure of the performance of the entire glazing system to control solar energy. The lower the heat gain, the better performance from the glazing system and hence the lower Shading Coefficient number.
Solar Heat Gain Coefficient (SHGC)
Is the measure of solar energy that is absorbed and transmitted directly in to the room through the glass. The lower the number the better efficiency and performance.
Emissivity (E factor)
Low E films are greatly beneficial to cold climate areas. Emissivity is the measure of a products ability to reflect radiant heat back in the direction of the source. For example, if you are heating a room, a Low E window film will direct a higher portion of heat back into the room than other window films. The lower the emissivity number the better its ability.
Glare is best known as bright light. It can enter rooms more so in the colder months when the sun is lower in the sky. It can reduce the ability to see clearly. Window film can significantly reduce Glare. Glare is measured as a percentage and is determined by the respective visible transmission values glass with and without window film
Ultra Violet Rejection
UVA is the major contributor to fade and Skin Cancers. Nearly all window film have almost 100% UV block and it is required to prolong the life of the film.
How does Solar Control Window film work?
Although very complex to manufacture its easy to understand how window film works in the diagram above. Without window film, solar radiation passes through glass without recognising it as a mass. It turns to heat when it contacts with a mass such as floors and furnishings. Window film simply creates a barrier between the glass and your home blocking and rejecting significant portions of solar radiation that turns to heat.
Solar control window film is one of the very few products that will save more carbon emissions “by reducing power consumption “that it takes to produce it. It looks good, assists with climate control and is now proven to be environmentally friendly.
The process of heat transfer by the movement of air. Doors and windows in buildings greatly contribute to this process.
The process of heat transfer through solid material like window frames from warm to cool surfaces.
More information at Wikipedia