Window Tint Percent: What 20%, 35% and 70% Mean
Window tint percent usually refers to visible light transmission, or VLT: the proportion of visible light that passes through the measured material or glass-and-film assembly. A lower VLT means less visible light passes through. It does not mean the same percentage of heat is blocked.
Silver Model X from the T-House window-tint archive. A photograph cannot establish the installed film's VLT; compare documented specifications and measurements.
Read the direction correctly
A nominal 20% film allows less visible light through than a nominal 35% film, while 70% is lighter. Treat these as descriptions of the specified product and test conditions. They are not guarantees of the final installed reading on every vehicle, and they do not identify whether the film is ceramic, dyed or another construction.
Account for the glass already on the car
The glass contributes to the final transmission. As a simplified illustration, glass transmitting 80% combined with film transmitting 70% gives about 56% when the fractions are multiplied. That illustration is not a measurement of your Tesla. Ask how the proposed combination will be assessed and record the film's nominal value separately from any installed-system measurement.
Do not turn VLT into a heat score
Two films with similar visible transmission can have different solar performance. XPEL's discussion of factory glass and window film explains why appearance alone is not enough to compare products. Request the actual series, shade and manufacturer specifications. Keep UV, infrared and overall solar measurements distinct rather than using a single number for everything.
Use the number to start a consultation
Explain the appearance you like, the windows involved and your visibility priorities. View actual samples in more than one lighting condition. The number alone is not a recommendation for any particular window, and this page does not establish which installation is permitted for your vehicle. Confirm applicable requirements and suitability before authorizing work.
Frequently Asked Questions
Is 20% lighter than 35%?
No. For comparable VLT measurements, 20% transmits less visible light and appears darker.
Does 70% film block 70% of heat?
No. Visible light transmission is not a heat-rejection percentage.
Will my installed VLT equal the film label?
Not necessarily. Existing glass and the measurement conditions affect the combined result.
Discuss your vehicle with T-House
T-House Auto Shop is at 527 Charcot Ave Suite 327, San Jose, CA 95131. Call (669) 677-2020. Bring the vehicle year, product information and photos relevant to your question so the shop can assess the next step.
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