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What do window tint specs mean?

5 min read · Polyshield Learn
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Short answer

VLT is how much light gets through: the lower the number, the darker the tint, and it is the figure tint laws use. UVR is how much UV the film blocks. TSER is how much of the sun’s total energy the film keeps out, and it is the best single number for comparing heat. IRR is infrared blocked at one wavelength (940 nm or 1400 nm), and SIRR is infrared blocked across a band. Compare films on TSER first.

VLT: Visible Light Transmission

VLT is the percentage of visible light that passes through the window. A 70% film lets most light through and looks almost clear. A 5% film lets very little through and looks close to black.

VLT is the number Australian tint laws use, and the limit applies to the glass and film together, not the film on its own. Factory glass already blocks some light, so a film usually measures darker once it is fitted. See How dark can you legally tint your car in Australia?

UVR: Ultraviolet Rejection

UVR is the percentage of the sun’s ultraviolet light the film blocks. UV is the part of sunlight that burns skin and fades and cracks dashboards, seats and trim.

UV blocking doesn’t depend on how dark the film is. A light, legal film can block as much UV as a dark one, so you don’t need a dark shade to protect your skin or your interior.

TSER: Total Solar Energy Rejected

TSER is the percentage of the sun’s total energy (ultraviolet, visible light and infrared) that the film stops from coming into the car as heat. It counts energy the film reflects away and energy it absorbs and releases back outside.

Because it covers the whole spectrum, TSER is the best single number for comparing how much cooler a film will keep the cabin. When two films have the same shade, the one with the higher TSER keeps more heat out.

IRR: Infrared Rejection at 940 nm and 1400 nm

Infrared is the part of sunlight you feel as heat on your skin, and it makes up roughly half of the sun’s energy. IRR is the percentage of infrared the film blocks at one specific wavelength. The number in brackets is that wavelength in nanometres (nm).

IRR (940 nm) is measured in the near infrared, just past visible light. IRR (1400 nm) is measured further into the infrared. Ceramic films are designed to block strongly at these points, so IRR figures are often high. Because each one is a single reading, it can look better than the film’s overall heat performance. Use IRR to compare films measured the same way, and TSER to judge real-world heat.

SIRR: infrared rejection across a band

SIRR measures infrared rejection across a range of wavelengths rather than at one point, as stated on the film’s data sheet. Because it covers a band of the infrared spectrum, it gives a fuller picture of infrared heat blocking than a single IRR reading.

Manufacturers don’t all measure SIRR over the same band, so only compare SIRR figures between films when the data sheets use the same range.

How to compare two tints

  1. VLT first. Make sure the shade is legal for the window it is going on.
  2. Then TSER. It is the best guide to how much cooler the cabin will be.
  3. Then UVR. For skin and interior protection.
  4. IRR and SIRR last. Useful supporting figures, not the headline.

A darker film isn’t automatically cooler. Nano ceramic film stops infrared heat even in light shades, so a lighter nano ceramic film can keep a car as cool as a darker carbon film. See Which window tint keeps a car coolest?

Polyshield tint figures

The figures for both Polyshield films, in every shade, are on the Window Tint page, alongside a shade picker that shows what is legal in your state.

Window tint

Talk to a Polyshield installer.

Get advice on the right film and shade for your car, and a quote.