Unfortunately, the window tint industry does not have a regulatory body to explain the truths and myths about tints. I'm hoping that i can shed some light in this from the feedbacks of satisfied customers from the USA. Fortunately, they provide us with a benchmark as all films imported to the USA are required to be tested on a standard form as required by The National Fenestration Rating Council (NFRC), AIMCAL and the IWFA. Below are excerpts from experts: -
Summarized: -
TSER is an industry recognized performance value, infrared rejection is not. TSER is the percentage of all energy from the sun reflected away from a window, as well as the percentage absorbed by the window and released back outdoors.
There are many problems with so-called "infrared rejection", such as the fact companies selectively choose which parts of the spectrum they report and IRR does not include absorption- an important contributor to heat gain. For instance, a certain large company reports this for only a small part of the spectrum which is less than 10% of the actual infrared wavelengths. Some other companies report this at only one wavelength! So they call it "infrared rejection", but really it is only a small part of the total infrared and is not representative of the actual infrared energy. Also, manufacturers of some products that have very high absorption report IRR because it does not count absorption against it. The TSER is the "true" heat rejecting value fo a film, because it takes the entire solar spectrum into account (infrared is only 49% of the solar energy anyway), and also includes the effects of absorption. The National Fenestration Rating Council is the the only third party window rating system. It is recognized by Energy Star, utility companies, and U.S. and Canadian governments. They only recognize SHGC/TSER. They do not recognize IRR.
In short, IRR is a misleading marketing gimmick.
The International Window Film Association also has a memo pointing this fact out, so check their web page out also. Additionally, CPFilms and Solar Gard have each written good white papers explaining why these claims are bogus (found on their technical pages).
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A quick check in Vkool and LLumar websites show that heat rejection ranges for their high VLT films(50-70%) are within 30-60% TSER. Pls be careful of bogus claims as these films cost in region of 1.5k to 6k sold in Malaysia. Hope this helps you understand heat rejection on your next purchase!