The rule in force and its source
Window light transmission is governed by Regulation No. 42 of the Minister of Economic Affairs and Communications of 13 June 2011, "Technical requirements for motor vehicles and their trailers and requirements for equipment", specifically Annex 1, code 612 "Glazing and field of view". The wording of the version in force since 1 January 2026 is as follows.
Code 612, point 1
The transmittance of the windscreen in the driver's field of view, and of the side windows forward of the backrest of the driver's seat in its rearmost position, must be at least 70%. If the transmittance of the windows behind that point is below 70%, the vehicle must have mirrors on both sides.
Point 5 of the same code prohibits covering glass with a material that increases the reflection of light from it, so mirror films are banned on every window. The full regulation and Annex 1 are on Riigi Teataja (in Estonian).
Many websites still quote older wording that required 75% for the windscreen. The text in force says 70% for both the windscreen in the driver's field of view and the front door windows.
What it means for each window
| Window | Requirement | In practice |
|---|---|---|
| Windscreen | At least 70% in the driver's field of view | Only a clear or very light film for UV and heat rejection, no dark tint |
| Front door windows | At least 70% including the glass | A very light film; most tint films do not qualify |
| Rear door windows | No requirement, provided the car has mirrors on both sides | Can be tinted as dark as you like |
| Rear windscreen | Same as the rear doors | Can be tinted; the heating wires keep working |
| All windows | Reflective films prohibited | Choose a grey or black shade, not a mirror |
Why a "70 film" does not give a 70% window
This is where most mistakes are made. The requirement applies to the window together with the film, not to the film alone. Factory glass is not fully transparent: a new car's side window passes around 75–85% of light, and a light factory tint even less. Put a film that passes 70% on such glass and the result is roughly 0.8 times 0.7, that is 56%. That is far below the limit.
On top of that, the shade a manufacturer names is a nominal value, not a measured result. For example, the measured light transmission of a LUNARAY NEX 70 film is about 72%, and that is the film alone. For a front door window to stay within the limit, the film itself needs to pass 88–90% or more. That is why serious installers offer only light or clear films for the windscreen and front doors, films whose value is in heat rejection rather than darkness.
How it is checked
Police and the roadworthiness inspection measure light transmission with a meter directly on the window, glass and film together. At inspection a windscreen or front door window below the requirement is a defect and the car fails until the film is removed. On the road a fine and an order to remove the film can follow. A good installer measures the result after installation and tells you the number.
What is allowed and still useful
Because the front windows cannot be dark, the sensible choice for the windscreen and front doors is a light nano-ceramic or graphene film that blocks 99% of UV and a large share of the heat while staying almost invisible. On the rear windows the shade is yours to choose: 35% is the common compromise between privacy and visibility when reversing, 5–15% gives a practically opaque surface. When choosing, look beyond darkness at the TSER value, the share of solar energy the film keeps out: two films of the same darkness can differ a lot in heat.
STEK LUNARAY tint films come in three series: NEX+ on graphene, SMART+ on nano-ceramic and ACTION+ on carbon, all with a lifetime warranty. Measured VLT and TSER values can be compared in the tint comparison, and an installer in your county is listed under window tinting.
Glossary: what the numbers mean
- VLT, visible light transmission in percent. The lower, the darker. The 70% in the law is the VLT of the glass together with the film.
- Nominal shade is the number the manufacturer names, such as 35 or 70. The measured VLT usually differs by a few percent, so compare the measured value on the data sheet.
- TSER, total solar energy rejected, shows how much of the heat the film keeps out. It is the real heat rejection figure and does not follow darkness directly: a light graphene film can keep heat out better than a dark dyed film.
- IRR, infrared rejection, is the part of TSER that advertising often shows on its own. Compare TSER instead, because it counts the whole spectrum.
- UV rejection is 99% on a quality film regardless of shade. It protects the interior from fading and your skin from the sun even with a clear film.
Before installation
- Ask the installer which measured light transmission the film for the front doors has and what the result is together with the glass.
- If you buy a used car with tinted front windows, have the transmission measured before the inspection.
- Do not choose a reflective film for any window.
- Keep the installer's warranty card: it shows the film type and shade if anyone asks later.
Frequently asked questions
Get a quote for your car
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