Technical analysis on types, legislation and benefits for comfort and safety
Driving in intense sunlight is a common challenge for drivers, impacting not only thermal comfort inside the cabin, but also safety and health. Prolonged exposure to sunlight can cause glare, visual fatigue and damage to the skin, in addition to overheating the vehicle’s interior and degrading components such as the dashboard and upholstery. The most effective technical solution to mitigate these problems is the application of solar control films to the windows. This guide details the importance of solar film, how it works, the types available and the legal standards that regulate its use, providing a complete overview for an informed choice.
Understanding the technology: what solar film is and how it works
Solar control film, popularly known as insulfilm, is a polyester laminate composed of multiple layers designed to filter and reject different spectrums of sunlight. Its effectiveness is not only measured by tone (darkening), but by a set of technical indicators that define its performance. The technology applied varies, including everything from simple dyeing to impregnation with metal or ceramic particles.
The main technical parameters for evaluating a film are:
- Visible Light Transmission (VLT): Percentage of visible light that passes through the glass with the film. The lower the value, the darker the film.
- Total Solar Energy Rejection (TSER): Total percentage of solar energy (visible, ultraviolet and infrared light) that the film blocks. This is the most complete indicator of thermal performance.
- Ultraviolet Ray Rejection (UVR): Ability to block UV radiation, the main cause of skin cancer and the fading of internal materials. Quality films block more than 99% of UV rays.
- Infrared Rejection (IRR): Percentage of infrared rays (responsible for the sensation of heat) that are rejected. A high IRR index results in greater thermal comfort.
Types of film and the importance of choosing the right one
The market offers different solar film technologies, each with specific performance, durability and cost characteristics. The appropriate choice depends directly on the driver’s needs, whether prioritizing aesthetics, thermal comfort or safety.
The main categories are:
- Basic (Dyed): Composed of layers of dyed polyester, it mainly offers privacy and reduced glare. Its heat rejection capacity (IRR and TSER) is low and tends to fade over time.
- Metallized Polyester (HP – High Performance): Adds a layer of metallic particles that reflects solar rays, significantly improving heat rejection. It has greater durability and color stability.
- Carbon: It uses carbon particles in its composition. It is not metallized, so it does not interfere with radio, GPS or cell phone signals. It offers good heat rejection and a matte, reflection-free finish.
- Ceramics: Considered the most advanced technology, it uses ceramic nanoparticles that are highly efficient in blocking infrared rays without the need to darken the glass excessively. It is the option with the best thermal performance and optical clarity.
- Anti-vandalism (Security): These are thicker films, designed to increase the glass’ resistance to impacts, making it more difficult to break and break into the vehicle. They can be combined with solar control technologies.
Legislation and compliance: what CONTRAN says
The use of films on vehicle windows is regulated in Brazil by the National Traffic Council (CONTRAN). Resolution No. 960/2022 establishes minimum light transmittance limits to guarantee driver safety and visibility. Disrespecting these rules is considered a serious infraction.
The current limits are:
- Windshield: Minimum luminous transmittance of 70%.
- Front side windows (driver and passenger): Minimum luminous transmittance of 70%.
- Rear side windows and rear glass: Minimum luminous transmittance of 28%.
- Roof glazing: There is no transmittance limit.
It is mandatory that the installed film has a seal, an indelible marking that informs the percentage of light transmission. Mirrored or reflective films are prohibited. Failure to comply with the legislation results in a fine, five points on the driver’s license and retention of the vehicle for regularization.
Investing in a quality solar film installed by a qualified professional is essential to ensure not only comfort and protection against the strong sun, but also compliance with the law. The technology goes far beyond aesthetics, acting as a functional component that improves safety by reducing glare, protects health by blocking UV rays and increases air conditioning efficiency by reducing internal heat. Therefore, the choice must be based on technical specifications (TSER, UVR, IRR) and respect for the light transmittance limits established by current legislation.
