What to Know About Car Window Tint

There are several reasons to jump on the blacked-out bandwagon.

Liane Yvkoff | 

Nov 13, 2023 | 3 min read

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Ultraviolet radiation oxidizes exterior paint, degrades rubber, and can wreak havoc on leather-swathed cabins. While the windshield does a good job of blocking UV light, the side and rear windows offer dramatically less protection from the sun. That's where window film comes in. It's a relatively inexpensive aftermarket upgrade that can help protect you and your car from harmful rays while potentially boosting your vehicle's curb appeal.

What Are Window Tints?

Window tints are thin sheets of laminate that block a certain amount of light from entering a vehicle. They offer varying degrees of visible light transmission (VLT) and can be applied to the side and rear windows of your vehicle, though restrictions vary by state.

These films protect the car interior from UV rays that fade fabric, dry out leather, and cause plastic to warp or crack. They can also protect the occupants from unnecessary sun exposure, providing a health benefit. Researchers at the St. Louis University School of Medicine found that there's a slightly higher prevalence of skin cancer in the United States on the left (driver's) side of the body than on the right.

Window tints will also generally keep the interior cooler. "The amount of temperature difference is going to vary by climate and VLT," said 3M application engineer Jess Meyer. "For instance, if you're driving during a sunny day in Florida, Arizona, or one of the hotter climates, you could feel a 25-degree temperature difference in your cabin from what's going on outside."

With a cooler cabin, drivers won't need to run air conditioning as long or as often, potentially saving fuel.

Tinted windows can make it harder for passersby to see what's inside the vehicle and, in doing so, might provide some protection against theft. The tradeoff is that they reduce outward visibility for the driver and passengers, particularly at night.

What Types of Window Tints Are Available?

There are several types of window films: dyed, metalized, carbon, ceramic, and crystalline.

Dyed films sandwich pigment between an adhesive layer and an outer protective coating. They're the most affordable option but the least effective at blocking UV light. They also tend to fade a bit over time, giving windows a purple hue.

Metalized tints rely on tiny metal particles embedded in the film to reflect light rather than absorb it. They are difficult to scratch and provide a nice shine. However, they can inhibit GPS, radio, and cellular use.

Carbon films won't fade or interfere with various signals and reduce cabin heat by about 40%. They're more expensive than dyed and metalized films but tend to last longer and hold up better.

Above that are ceramic tints, which provide the best protection from the sun, blocking up to 99% of UV light while reducing glare. This, of course, demands a premium.

Lastly, there are crystalline tints, which are essentially clear. They block the sun's rays without reducing outward visibility but provide no privacy.

Are Aftermarket Window Tints Legal?

The minimum allowable VLT varies from state to state and often from window to window. They're not permitted on the windshield except when the driver has an approved medical reason for it. (Some states also allow car owners to add a film along the top of the windshield.) Another thing to keep in mind: Automotive windows typically provide some level of UV protection from the factory. You need to factor this into the VLT calculation when choosing an aftermarket tint.

Should You DIY or Hire a Professional?

YouTube videos have made it a lot easier for novices to tackle the job. However, cutting and applying the film without leaving light gaps, creases, or bubbles is more difficult than it looks. If those things will bother you, it's best to outsource the work to your dealership, a body shop, or professional installer.

Liane Yvkoff

Liane is an automotive technology and lifestyle writer covering alternative powertrains, transportation startups, next-generation infotainment systems, and just about anything else that could “disrupt” your daily commute. Her work has appeared online and in print.