VLT — the only number that matters
VLT stands for Visible Light Transmission: the percentage of light that gets through the window. Higher is lighter. A 70% film lets 70% of the light through; a 5% film — “limo tint” — lets 5% through.
The number that counts is the combined VLT of the glass and the film together, not the film on its own. Factory glass is not perfectly clear, so a 70% film on typical factory glass lands you below 70% combined. A good installer accounts for this; it is one of the practical differences between a professional job and a cheap one.
The limits, window by window
| Window | What California allows |
|---|---|
| Windshield | Top 4 inches only (the AS-1 line). Nothing below it. |
| Front side windows | Must transmit 70% or more of light. Effectively a very light film. |
| Rear side windows | Any darkness. |
| Rear windshield | Any darkness — but if it is tinted, the car must have working side mirrors on both sides. |
Reflective and mirrored films are separately restricted, and red and amber tints are not permitted on any window. Those two catch people who buy film online.
What happens if you are over the limit
Illegal tint is normally written as a “fix-it” ticket — a correctable violation. You remove the film, have the correction signed off, and pay a modest dismissal fee. It is not catastrophic, but you have paid for film twice and lost a morning at the courthouse.
The one to avoid is a repeat. A second citation for the same thing is not treated as correctable in the same forgiving way, and the fine goes up.
The medical exemption
California allows darker front-window tint for people with a documented medical condition made worse by sunlight — lupus, certain photosensitivity disorders, some skin conditions. It requires a signed letter from a licensed physician or optometrist, kept in the vehicle.
It is a real exemption and it is under-used. If it applies to you, get the letter before the film goes on, not after a traffic stop.
How to get the benefit without breaking the rule
Almost everyone who wants dark tint actually wants a cool car, and darkness is a poor way to get one. Heat is carried by infrared, not visible light, and a good nano-ceramic film rejects most of the infrared while staying legally light.
A 70% ceramic film on the front doors rejects far more heat than a 20% dyed film, and it is legal. That is the whole argument for ceramic in a valley climate: you stop paying for darkness and start paying for the thing you actually wanted.
Need this done rather than explained? There is no shop to drive to. We come to wherever your car already is — your driveway, your workplace car park, an apartment lot, or the side of the road it stopped on — anywhere in greater Sacramento, with no call-out fee and no mileage charge. Give us the year, make and model and you will have a firm price before the call ends.