VLT % Explained for Saudi Tint Law: Why It's Not the Same as Heat Rejection

What Exactly Is VLT (Visible Light Transmission)?

VLT stands for Visible Light Transmission. It is simply the percentage of visible light — the light your eye can see — that successfully passes through the glass and film together into the car.

If VLT equals 70%, it means 70% of daylight enters and only 30% is blocked, which is a near-clear glass. If it is 30%, then 30% of light enters and 70% is blocked, which is a relatively dark glass.

The lower the VLT number, the darker the glass, and vice versa. This specific number is exactly what the Tint Meter device measures at checkpoints and during periodic inspection, because it is the only figure tied to the driver's and pedestrians' vision at night.

Saudi local shade grades translate into approximate VLT percentages: shade 00 means clear glass (around 70% and above), while shade 02 — allowed for rear side windows — equates to roughly 30% VLT. The crucial point is that VLT tells you nothing about heat; a film at 70% light could be a premium cooler or thermally useless — all of that depends on the film's technology, not its color or transparency.

Heat Rejection Is a Totally Different Thing: IR and TSER

The heat you feel inside a car does not come from visible light as much as it comes from an invisible part of the sun's spectrum called infrared (IR). Because these rays are invisible, a film can block them heavily without making the glass dark at all.

This is where two numbers entirely separate from VLT come in. The first is IR Rejection; in the original nano-ceramic films we install at AzelCore, this figure reaches 96–97% according to the thermal measurements we conducted on samples in Jeddah.

The second, and the more scientifically accurate and important one, is TSER — Total Solar Energy Rejected — which combines the effect of light, heat, and ultraviolet into a single number representing the film's true thermal performance; 3M Crystalline, for example, reaches a TSER of around 90% even though it is nearly transparent. Bottom line: IR and TSER tell you how much the film will cool your car, while VLT only tells you how dark the glass will be — and the two do not necessarily move together.

What Saudi Law Actually Regulates — VLT Only

This point is the heart of the article: the General Directorate of Traffic in Saudi Arabia regulates the VLT number only, and mentions neither IR nor TSER nor "heat rejection" in any requirement. The reasoning is entirely logical; the law protects vision and road safety — a security officer needs to see inside the vehicle, and a driver needs to see pedestrians at night, all of which relate to visible light alone.

So the requirements come by glass position: the large front windshield and the driver/passenger side windows must be clear (shade 00, around 70% VLT and above), and clear heat-rejecting film may be installed on them as long as it does not change the glass color and is not reflective. The rear side windows may be dimmed up to shade 02 (around 30% VLT) for privacy.

The violation fine falls under "making a modification to the vehicle's structure" and ranges from 500 to 900 SAR. The striking practical meaning of this framework is that there is no legal upper limit on heat rejection at all; you can legally install a film that blocks 97% of infrared on the windshield, 100% compliant, as long as VLT stays at 70% and above.

Why a Dark Film Does Not Mean a Cool Film

This is the biggest paradox car owners pay for: they buy the darkest film on the market thinking darkness equals coolness, and they end up with a traffic violation and hot glass at the same time. Cheap dyed films work via a black dye that absorbs light, making the glass very dark (low VLT), but they contain no ceramic layer or treatment to block infrared, so their IR figure stays low.

The result is a car that looks dark from outside but feels like an oven inside — plus it is illegal on the front windows. In our field thermal measurements across ten Jeddah districts using a FLIR camera, we recorded that a car with no real insulation reaches a cabin temperature of around 77°C, while it drops to about 40°C with an original nano-ceramic film — and that gap is caused by the high IR figure, not the film's color.

On the other hand, a near-clear nano-ceramic or 3M Crystalline film (high VLT) can be three times cooler than a cheap black film. So the golden rule: always ask about IR and TSER, and do not let the darkness of the glass deceive you.

The Inspection Trap: Factory Glass Already Has Tint

Many people fail periodic inspection even though they chose a film "in an allowed shade," and the reason is purely numerical, about how VLT percentages stack. Original factory glass from the dealership is not 100% clear; it carries a light tint usually between 5% and 10% for safety and basic factory insulation reasons.

When an unprofessional technician installs a film supposedly rated at 30% transmission (shade 02) on top of it, the two percentages compound rather than staying at 30%; the combined total transmission drops below the allowed limit, and the glass fails the inspection Tint Meter. This is a fine point many centers overlook.

The correct method we follow at AzelCore is to measure the original glass transparency first with the device before any installation, then choose the film that ensures the final combined percentage stays within the legal limit. Sometimes this means selecting a film with a nominal transmission slightly above 30%, so that after installing it over the factory glass it lands exactly on the correct figure.

Understanding VLT properly here is not theoretical luxury; it is the difference between passing and failing the inspection.

How to Read a Film Certificate and Understand Its Numbers

Every original film from Johnson, 3M, or LLumar comes with technical specifications stating at least three numbers, and it is your right to request them written on your invoice and warranty certificate. The first number is VLT, sometimes written as a percentage or as a shade name (CR70 in 3M means around 70% light transmission).

The second is IR Rejection, expressing the percentage of near-spectrum infrared blocked; the closer it is to 95% and above, the better the thermal performance. The third and most important is TSER, which combines total performance.

Beware of the common trick: some sellers show an "IR at a single wavelength" figure (such as 1000 nanometers) and write it as 99% to dazzle you, while the film's real TSER is far lower. Always ask for TSER because it is the metric that cannot be dressed up.

At AzelCore, being an authorized dealer for Johnson and 3M means the figures we provide come from the manufacturer's official specifications, not anonymous labels, and that the certificate carries the actual VLT percentage for each window to be your shield before inspection and checkpoints.

Choosing the Right Film: Clear, Cool, and Compliant

Once you understand the difference between VLT and heat rejection, the choice becomes logical and simple. For the windshield and front side windows (where the law obliges you to keep a high VLT around 70%), the ideal solution is a film with high light transmission but very high IR and TSER — which is exactly what films like 3M Crystalline, Johnson Supreme IR, or clear nano-ceramic offer; glass that is nearly clear to the eye, fully legal, yet blocks the vast majority of heat.

As for the rear side windows, you have more freedom up to shade 02 (around 30% VLT) if you want greater privacy, while still choosing a nano-ceramic film to combine darkness with genuine thermal insulation. At AzelCore, a full nano-ceramic tint for a sedan ranges from 1,500 to 2,200 SAR with a 10-year warranty, and 3M Crystalline from 2,000 to 2,800 SAR with a lifetime warranty, both staying within the legal VLT limits.

The final rule: let the law decide the VLT number, and let your comfort decide the IR/TSER number — and never mix the two.