Claims about “infrared rejection” are not all that one needs to review to find the best window tint.
Although IRR is abundant in current marketing literature the claims that are being made do not reflect the true performance of the product in rejecting heat.
This methodology results in an incomplete assessment of the solar infrared energy, since the energy across the infrared portion of the solar spectrum varies widely, 780 to 2500nm.
Visible light, IRR, UVR et al
In understanding comparison charts and graphs, measuring IRR at a single point or in a small range does not encompass the total amount of heat gain caused by the infrared component of the spectrum.
It is critically important to become informed about the entire solar energy spectrum, not just one factor in the range, as well as the additional effects of absorption on heat gain.
The Solar Spectrum is made up of UV, Visible light, Infrared or NIR.
Ultraviolet Light (on the left) falls between 100 nm to 380 nm and is not visible to the human eye.
This light is highly energetic (can tan your body) and destructive (in excess can give you skin cancer). In the case of your car it can cause damage by burning or fading the colors of its interior decoration if allowed to go through. This is why UVR (UV Rejection) is an important measure that should always be as high as possible +99%.
However when considering the amount of heat energy UVR carries is small compared to the amount of heat energy contained by visible and infrared light.
Visible Light reaching the surface of the earth that can be seen by humans is located between the wavelengths of 400 and 780 (nm) in the spectrum (the seven colors from violet to red).
The remaining type of light is Infrared Radiation. The near-infrared portion of the solar spectrum runs from approximately 780 nm to 2,500 nm and carries about 49% of the solar energy – just under half of the total solar energy.
We have recently included in all our product descriptions information about the light transmittance. In our graphs transmittance is represented by the blue line which measures how much of each type of light is passing through the film.
When comparing film the wavelength used in graphs follows the spectrum of light explained above. It goes from UV on the left (high frequency with short wavelength) to infra-red on the right (low frequency with long wavelength)
So the lower wavelength (300) means more red starting off from UV (300 - 380 nm). Then they move to less thin waves into visible light (380-780nm) and finally to wider waves which represent red and infra-red at 780-2500 nm.
Applied to our film for example, GLASSTINT Shure X allows very few IR to pass through when compared to other tinting film products. This is due to darker shades being more reflective. Why ceramic tinting film is the best, read here.
Conclusively, an effective window tint against sun is one with a high rejection rate for IR and UV and at the same time allowing in a comfortable VL level.
GLASSTINT is a window tinting brand based in Korea that is reaching the world through its partner network. Your car deserves the best. Find your nearest tinting shop. You can become our partner, read more here.