Does plain car glass block UV?
Partly. Car glass stops nearly all UVB, the shorter-wavelength UV, but lets some UVA through, and windshields stop far more UVA than side glass.
The Skin Cancer Foundation puts it plainly: “Window glass does a good job at filtering out most UVB rays”, while UVA rays “pass through windows and clouds year-round.” The difference is in the construction. A windshield is laminated: two layers of glass with a film interlayer sandwiched between them. The door glass, the back window and the sunroof are usually tempered instead, one sheet with nothing in between.
| Glass | Where it’s used | UV figure | Source |
|---|---|---|---|
| Laminated | Windshield | About 99% of UV cut | AGC, glassmaker |
| Tempered | Front doors, rear doors, back glass | Around 90% of UV cut | AGC, glassmaker |
| Clear, non-laminated (lab sample) | Typical of side glass | Let through 62.8% of UVA | Hampton et al., 2004 |
| Grey laminated (lab sample) | Tinted laminated glass | Let through 0.9% of UVA | Hampton et al., 2004 |
AGC credits the windshield’s interlayer film for its high UV cut, and doesn’t split its figures into UVA and UVB. The lab samples come from a 2004 British Journal of Dermatology study, which also found that tinted glass let through less UVA than clear glass, and laminated less than non-laminated.
How much UVA gets through the side windows of real cars?
Far more than through the windshield, and it swings from car to car. Two studies metered the glass of real vehicles:
| Study | Vehicles | Windshield, UVA blocked | Driver’s window, UVA blocked |
|---|---|---|---|
| JAMA Ophthalmology, 2016 (Boxer Wachler) | 29 cars from 15 makers, model years 1990 to 2014 | 96% on average | 71% on average; just 4 of the 29 over 90% |
| Archives of Dermatological Research, 2025 (Axelson and colleagues) | 34 vehicles (15 gas, 9 hybrid, 10 electric), model years 2015 to 2025 | 99.25% on average; lowest 91.67% | 88.78% on average |
Every window, measured in the 2025 study
The newer study measured every window; the front side glass came out weakest:
| Window | UVA blocked, average of 34 vehicles |
|---|---|
| Windshield | 99.25% |
| Driver’s window | 88.78% |
| Front passenger’s window | 88.99% |
| Rear left window | 93.18% |
| Rear right window | 95.57% |
| Back glass | 95.36% |
In the study’s vehicle-by-vehicle table, 18 of the 34 driver’s windows blocked under 90% of UVA, and 13 blocked all of it. Every window blocked 100% of UVB except one: the rear left window of a 2024 Honda CR-V, at 37.5%.
Same model, different year
The make and model don’t tell you what your glass does. In the same table, a 2019 Tesla Model 3’s driver’s window blocked 81.25% of UVA and a 2023 Model 3’s blocked 100%. A 2016 Toyota RAV4 blocked 92.5%, and a 2022 RAV4 73.53%. The authors couldn’t always tell what glass each car had or whether a window had been replaced, but the spread is the point: a model name is no guide to the UVA coming through your door glass.
How much UV does window film block?
Over 99%, on every film the shop sells. LLumar’s performance data sheet gives each automotive film it lists, darkest to clearest, a UV figure of more than 99%, measured from 300 to 380 nm.
| LLumar film | Visible light let through (VLT) | UV blocked, 300–380 nm |
|---|---|---|
| ATC 05 | 5% | >99% |
| ATC 50 | 60% | >99% |
| IRX 50 | 54% | >99% |
| AIR 80 | 77% | >99% |
| AIR 90 | 84% | >99% |
The Skin Cancer Foundation’s figure for window film is the same: above 99%, for UVA and UVB alike.
A note on wavelengths
The film rating and the car studies don’t measure the same band. LLumar rates its films from 300 to 380 nm; the 2025 study’s UVA meter read 320 to 400 nm and its UVB meter 250 to 320 nm. Treat the film and glass figures as answers to slightly different questions.
Does darker tint block more UV?
No. The shade of a film measures visible light, and UV protection is a separate property. On LLumar’s sheet, ATC 05, which lets in 5% of visible light, and AIR 90, which lets in 84%, carry the same UV rating.
Lisa Winckler, a technical consultant to the International Window Film Association, wrote for the Skin Cancer Foundation that “darker tints do not protect against UV rays any better than clear UV-protective film does.” She also notes that most side and rear windows and sunroofs block only UVB, leaving skin exposed to UVA.
So shade isn’t a UV measure. A dark window feels protective because it cuts glare, but the darkness you see says nothing about the UV you can’t. If UV is the reason you’re tinting, pick the shade for its look: near-clear LLumar AIR does the same UV job as blackout film. For the shade question itself, see how dark tint can be in BC.
Which windows can you put UV film on in BC?
Everything behind the driver, the glass that already did a little better in the 2025 study. The two front side windows, the weakest, can’t legally take film.
MVAR s. 7.05(8) limits film to three places: side glass behind the driver’s seat, the rear window of a vehicle with a mirror outside on each side, and a band along the windshield’s top edge no more than 75 mm deep. It sets no exception for clear film, so even near-clear AIR on a front door window is not road-legal. The shop installs it there when a customer asks, after explaining the ticket and Notice & Order risk. BC has no medical exemption either; the legal alternatives are on the medical exemption answer.
Roof glass is its own case, covered on the sunroof tint page. What the numbers mean for skin is on does window tint help prevent skin cancer.
Booking UV film for the glass behind you
Ask for any LLumar film on the rear doors, quarter windows and back glass; for UV alone, the shade is up to you. ATC rear-glass packages range from $220 to $260 depending on the body, and clear AIR is priced per package on top.
The price list has every package. Send the vehicle details through the quote request, or ring or text 604 534 6433; on most cars the work takes one visit.