When researching or purchasing window films, we often here words like VLT, IR, TSER, UV but what do they actually mean? What’s the difference? Well, worry no more as we are here to help you. With all these terminologies, it can be pretty overwhelming. So let’s break it down so that it will be easier for you to understand!

UV: Ultraviolet

Ultraviolet is electromagnetic radiation with a wavelength from 10 nm to 400 nm. UV radiation is present in sunlight and this is what causes the most damage to our eyes, skin and furnitures.

UVR: Ultraviolet Rejection

The percentage of UV that is rejected. In the window film market nowadays, it can go as high as 99%. This is important and one of the main point that everyone needs to look for while purchasing window films/tints.

VLT: Visible Light Transmitted

Visible light transmitted is the ratio of visible solar energy (380 – 750nm) that passes through the glazing system. VLT value is the percentage of visible light the film/tint allows through from the exterior of a vehicle, building or home to the interior. Based on your preference, this determines how much light you want to enter.

The lower the VLT percentage, the darker the tint is and the more outside light it blocks. For example, a window film/tint that has a VLT value of 5% indicates that the window film only permits 5% of the exterior light to pass through and enter while a film with a 50% VLT value allows 50% of the light from outside to pass through.

In the market, when professionals are referring to a film/tint, they typically identify it by the film/tint’s colour and VLT value (percentage). For example, a charcoal coloured tint with a VLT of 5% is known as charcoal 5%. Likewise, a green coloured tint film with a VLT of 50% is called green 50%. This will give you a gist of how window film/tint suppliers and retail shops name their product range. So if you hear someone says charcoal 5%, you will automatically know the colour is charcoal and the VLT is 5%, which means it’s pretty dark inside as only 5% of light is allowed in.

IR: Infrared

Infrared radiation is electromagnetic radiation with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye. It is sometimes called infrared light. To sum it up, we cannot see it with our eyes but we can feel it. It’s basically heat!

IRR: Infrared Rejection

The total infrared light (IR) rejected.

TSER: Total Solar Energy Rejected

Total Solar Energy Rejected is the percentage of the total solar energy that is rejected. TSER includes all three: visible light, infrared and ultraviolet. The higher the percentage, the higher the percentage of solar energy deflected. Most window film/tinting shops use Infrared Rejection (IRR) as a guide to the level of heat rejection but IRR only covers 1/3 of TSER. Internationally, TSER is used as a guide as it is a more accurate way of measuring heat rejection as it includes all three (visible light, infrared and ultraviolet).


Ply is used to display the number of separate layers of polyester film that are used in the manufacturing process to make a particular window film product. Example: A 1-ply product would consist of one single layer of polyester film where a 3-ply product would be made with three separate layers of various types of polyester film.


Mil is the unit of measurement equal to one thousandth of an inch (.001”). Basically, to know how thick or thin a film/tint is, you will need to refer to Mil. 1 MIL = 25 micron. There are many options in the market, ranging from 2mil, 5mil all the way to 12mil.

We hope this has been useful to you! With this basic knowledge, you can easily understand the features of window films better when choosing the suitable ones based on what you’re looking for.

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