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How much darker, cooler, and safer is window film tint? Go how far into the night? Explained are VLT, UV, IRR, and TSER

According to the rules under Motor Vehicles (Prohibition of Certain Types of Glass) (Amendment) Rules 2016. The Darkness or known as Visible Light Transmission (VLT) of the front windscreen is 70%; Front windows is 50%; and rear windows and rear windscreen has an unlimited choice of VLT. Which means, drivers may choose any VLT for it, no matter if you choose a 0% of VLT, total block your view will be fine. 

Drivers may consider, ‘how dark should I go?’ More of that is anticipated from drivers in order to increase their safety, privacy, and lower interior car temperature—especially because Malaysia has year-round summer. But keep in mind that darker doesn’t always mean better, at least not in terms of opacity-based performance. The common belief is that a darker window film will provide better protection from the damaging effects of sunlight and lower interior cabin temperatures, however this isn’t always the case.

The quality of the window film is crucial, and choosing the one that is the darkest possible may just result in visibility problems with no appreciable heat rejection performance. Let us explain the most important elements you must understand before you are looking for any film to install on the car window. The VLT, UV, IRR and TSER.

Modern automobiles often have laminated glass for the front and rear windscreens and tempered glass for the side windows as their glazing material. Here, the VLT level refers to how much light in the visible spectrum can travel through the glazing material; the higher the VLT number, the more light can pass through. Unfortunately, it also adds heat from the sun.

Solar Heat Give You Many Impacts

In order to lessen the impacts of solar heat, modern car glazing materials, most notably laminated windscreens, typically contain some level of coating or tint. This lowers the VLT level of that specific surface. Depending on the automaker, this might be barely audible or obvious.

In a hard environment like ours, this is obviously insufficient, which is where window films come in, since there is also tempered glass on the sides, which often has no discernible solar gain control performance. A decent window film lessens the negative impacts of solar energy as well as the amount of light that enters the cabin.


UV radiation comes in the forms of UVA and UVB, with UVA being more prevalent and having a longer wavelength. UVA is also responsible for fading and deteriorating exterior paint as well as interior materials like leather and fabrics, while UVB causes sunburn and other harmful skin conditions. The better the film’s UV rejection percentage, which most high-performance films achieve at 99%, the higher the percentage.

Infrared light accounts for the majority of the heat you experience inside a car; therefore, the higher the percentage of rejection, the higher the amount of infrared rays rejected. The IR wavelength spectrum is broad, however most window film specifications only cover a portion of the whole envelope and nonetheless list a 99% IR rejection. As a result, a high infrared rejection rate isn’t the only factor to consider. 

Film Performance and Range
Total solar energy rejected or known as TSER. While not an absolute indicator of a film’s performance, TSER represents the proportion of total solar energy that the filmed glass rejects. The lower the transmission of solar heat into the cabin, the greater the percentage number.

Although measured percentages of numerous high-performance films indicate higher TSER in darker versions of a certain range, supporting the notion that a darker tint is cooler, it is typically restricted to a like-for-like comparison and is range specific. This means that, despite the latter’s darker characteristics, the IRR and TSER of a range-topping 60% VLT film is significantly better than that of mid- and entry-level series offerings of 40% VLT from the same manufacturer.


Drivers may consider more about the clarity when driving, glare reduction is a factor that some businesses add even though it is not a requirement because it is related to opacity. Only in terms of glare reduction does a darker film clearly outperform a lighter one. This is because more light is filtered out before entering the cabin, just like how sunglasses reduce glare for their wearer.

Good Film Give You Anything You Want

Clarity isn’t a criteria to gauge solar gain control effectiveness, either, as it again comes down to a film’s quality. You get what you pay for, as inexpensive films don’t endure (fading, bubbling, waviness), and visibility through them isn’t going to be fantastic, more so as they age. A low grade dyed film with weak or nonexistent UV and IRR rejection may keep light transmittance low but won’t keep the heat out.

At this point, it’s also important to disprove the myth that deeper hues are safer. A dark colour doesn’t make something “safer” or more durable, save from keeping out inquisitive eyes. Despite what a recent news item claimed, a darker window coating won’t by itself make it more difficult for rescue services personnel to enter a vehicle in an emergency.

Security and Safe

The manufacturing characteristics of a window film determine its tensile strength, therefore security films naturally have greater impact resistance. Due to the possibility of security films being transparent, clarity alone does not accurately reflect a film’s strength.

Although driving in extreme darkness could make your automobile look awesome, remember that visibility is crucial for road safety. According to a recent news story, Lim Bee Choo, president of the Malaysian Automotive Accessories Traders’ Association, expressed his organization’s concern about road safety if the rear windscreen were blackened out. she noted that while visibility is generally not a problem during the day, the same cannot be said at night.

She continued by saying that many customers regretted having their back windscreens tinted so darkly because it was difficult to see the road clearly, especially at night or in the rain. Lim said that a film’s ability to reflect heat was not necessarily increased by a darker colour.

Advice for Higher VLT to Improve Visibility

Because of the same problems with decreased visibility, a few window film installers that we spoke to said they would not advise completely darkening the back windows and windscreen. While a VLT level of 10% or less for the rear side windows is still considered adequate for driving safety, they advised that reduced visibility when exiting side parking should be taken into account when making a choice.

The rear glass should be quite clear, with a minimum VLT decrease of 15-20% being advised for clients who prefer to darken the back. At this point, a rear-view camera should unquestionably be considered.

They Said That a High-quality Window Film Offers Sufficient Solar Gain Control Performance

Without the need to completely black out windows, and that choosing this particular path mainly involved reducing rear cabin glare, increasing privacy considerations, and adding cosmetic appeal.

They emphasised that customers should consider the window film’s quality and performance rather than relying solely on opacity to define performance. They also added that customers should choose the best film they can afford rather than choosing something from a lower, less effective range just because it has a version with a higher opacity.

The Worth of High Quality Film

Since a cheap, heavily dyed film won’t keep the cabin cooler than a good grade film with strong TSER characteristics, consumers need to get rid of the idea that darker colours of window films provide better heat rejection and safety.

The counsel of the experts? Even if it’s not the darkest movie you can find, stick with well-known companies and the greatest movie you can afford. If a company offers an infrared heat-emitter to compare their window film side by side, be sure to use it to have a better understanding of the situation.

Removable window screens are another choice that offers extra VLT reduction without the trouble of a fixed installation. If you already have relatively black window film—for instance, if it falls inside the previously stated 30% VLT level for the rear—that’s a path worth taking.


Darker, Cooler, and Safer


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