Selecting the right window tint for your car can make a big difference in keeping the interior cool on hot summer days. The level of heat protection offered by tint depends on the type of tint, the darkness or visible light transmission (VLT) percentage, and proper installation. With so many tint options on the market, it can be challenging to determine which one provides the best cooling effect for your needs and local climate conditions.
How Does Window Tint Keep a Car Cool?
Window tint works by reducing the amount of solar energy that passes through the glass and enters the vehicle interior. Non-tinted auto glass allows up to 85% of the sun’s infrared rays to penetrate the cabin. These rays get trapped and heat up the air inside the car.
Tinting films reject and absorb heat before it passes through the glass. The particles in the tint scatter and reflect solar radiation back outward. Darker tints block more of the visible light spectrum, while still allowing visibility, and are more effective at cooling. However, even lighter tints make a noticeable difference in temperature reduction.
In addition to lowering interior temperatures, tint provides other benefits like blocking UV rays to protect skin and interiors from sun damage, reducing glare, and adding privacy. Properly installed window film can also enhance occupant safety by holding shattered glass together in the event of an accident.
Factors That Impact Performance
Many variables influence the cooling capabilities of auto tint. The major factors to consider are:
- Film Type – Dyed, hybrid/ceramic, and metallic/carbon films have different heat rejection properties.
- Visible Light Transmission (VLT) Percentage – Measures how much visible light passes through. Lower percentages denote darker tint.
- Film Thickness – Thicker tint blocks more infrared rays.
- Number of Layers – Multiple layers enhance heat reduction.
- Window Type – Performance varies on laminated vs tempered glass.
- Vehicle Features – Sunroofs and large windows lead to more heat gain.
- Climate Conditions – The hotter the environment, the more heat reduction is needed.
A high-performance tint designed specifically to keep cars cool will take all these factors into account.
Visible Light Transmission Recommendations by State
The legal limit for visible light transmission percentage allowed on front driver and passenger windows varies by state. It ranges from no tint permitted to 50% VLT minimum. Check your local state laws before applying dark tint to the front. Here are some state-by-state recommendations:
| State | Recommended Front Window VLT % |
|---|---|
| Alabama | 32% |
| Alaska | 50% |
| Arizona | 33% |
| Arkansas | 35% |
| California | 70% |
| Colorado | 27% |
| Connecticut | 35% |
| Delaware | 50% |
| Florida | 28% |
| Georgia | 32% |
| Hawaii | 35% |
| Idaho | 35% |
| Illinois | 35% |
| Indiana | 30% |
| Iowa | 70% |
| Kansas | 35% |
| Kentucky | 35% |
| Louisiana | 40% |
| Maine | 35% |
| Maryland | 35% |
| Massachusetts | 35% |
| Michigan | 35% |
| Minnesota | 50% |
| Mississippi | 30% |
| Missouri | 35% |
| Montana | 32% |
| Nebraska | 35% |
| Nevada | 35% |
| New Hampshire | 35% |
| New Jersey | 50% |
| New Mexico | 43% |
| New York | 70% |
| North Carolina | 35% |
| North Dakota | 50% |
| Ohio | 50% |
| Oklahoma | 25% |
| Oregon | 35% |
| Pennsylvania | 70% |
| Rhode Island | 35% |
| South Carolina | 35% |
| South Dakota | 27% |
| Tennessee | 35% |
| Texas | 25% |
| Utah | 43% |
| Vermont | 35% |
| Virginia | 50% |
| Washington | 35% |
| West Virginia | 35% |
| Wisconsin | 50% |
| Wyoming | 29% |
The rear and back seat windows can accommodate much darker tints, usually ranging from 15% to 5% VLT while still being street legal. A 5% VLT film on the rear glass provides maximum heat reduction and privacy.
Types of Automotive Window Tint
There are three main categories of tint – dyed, metallic, and ceramic/hybrid ceramic film. Each has pros and cons for heat rejection and performance:
Dyed Window Tint
Dyed tint contains colored dyes within the adhesive applied to the film. The dyes absorb light and reduce glare and heat. Dyed films are the most affordable option and provide decent UV blocking. However, the dyes tend to fade faster over time. This type only blocks up to 50% of infrared rays.
Metallic Window Tint
Metallic tint incorporates tiny metal particles in the adhesive that reflects solar energy. The layered metal structure makes this film very effective at heat rejection – blocking up to 90% of infrared light. Metallic tint maintains its color and performance longer than dyed versions. However, it can interfere with radio reception and cellular signals.
Ceramic Window Tint
Ceramic particles are integrated into nano-carbon films to absorb more heat than traditional metallic tint. Advanced non-metallized ceramic tint provides up to 97% infrared radiation blockage while allowing better light and radio wave transmission. Hybrid ceramic is layered with both ceramic and metal particles for enhanced effectiveness. But it costs more than other options.
Additional Recommendations for Maximum Cooling
To get the full benefits of window tinting for keeping your car cool, here are some extra recommendations:
- Tint all windows, including the windshield if allowed by law
- Use a darker tint with low visible light transmission in the rear
- Choose a thicker mil film, usually 4 to 5 mil thickness
- Opt for dual-layer or multi-layer tint
- Use a carbon or ceramic-based tint for best heat rejection
- Make sure there is proper air circulation in the car to vent hot air
- Park the vehicle in shaded areas whenever possible
High temperatures, extended sun exposure, and large window areas can overwhelm a lesser quality tint. The best way to keep interiors cool is to use the darkest legal VLT tint on all windows paired with a technologically advanced ceramic or carbon-based film.
Conclusion
Installing thermal blocking window tint is an effective way to reduce heat and maintain cooler conditions in a hot car. The level of heat reduction depends on the type of tint, the darkness, number of layers, proper coverage, and a high-quality professional installation. While rules vary for visible light transmission percentages allowed on the front windows based on your state, the rear and sides can accommodate much darker tints up to 5% VLT for maximum cooling and privacy. Advanced ceramic or carbon films provide the best heat rejection by blocking up to 97% of infrared rays.
