A lot of new SUVs, trucks and vans come with dark back windows from the factory. So one of the questions we hear most is, “My car is already tinted. Do I need window film?”
The short answer: factory tint and window film look alike, but they don’t do the same job. Here’s the difference, in plain English.
What is factory tint?
Factory tint, also called privacy glass, is glass that gets its dark color when it’s made. The color is in the glass itself, so it won’t peel, bubble or fade.
You’ll usually find it on the back windows of SUVs, trucks and vans. Your front door windows almost always come lighter from the factory.
Factory tint is mainly there for looks and privacy. It makes the back of the vehicle darker, but it doesn’t block much of the sun’s heat.
What is window film?
Window film is a thin layer we put on the inside of your glass after the car is built. Good films do much more than darken the window. Depending on the film, they block heat, cut glare and stop almost all UV rays.
We install 3M window film, in four levels:
| 3M film | Level | Blocks up to this much infrared (IR) heat, the heat you feel from the sun |
|---|---|---|
| 3M Obsidian | Good | 9% |
| 3M Color-Stable IR | Better (most popular) | 40% |
| 3M Ceramic IR | Best | 95% |
| 3M Crystalline | Premium | 98% |
The heat numbers come from our Price Guide, which has 3M’s brochures for each film.
Factory tint and UV
Many people assume dark glass blocks UV. It doesn’t always.
In a 2016 study in JAMA Ophthalmology, front windshields blocked about 96% of UVA rays on average, while side windows blocked only about 71%. That matters if you spend a lot of time driving, especially on the driver’s side.
Window film fixes that. It adds UV protection to the glass you already have.
Factory tint vs window film at a glance
| Factory tint | Window film | |
|---|---|---|
| Where it is | In the glass | On the inside of the glass |
| Which windows | Usually the back windows only | Any side window and the rear windshield |
| Heat blocking | Not much | Up to 98%, depending on the film |
| UV blocking | Varies | 99% or more |
| Can you change it? | Only by replacing the glass | Yes. It can be removed and replaced |
| Looks | Dark and even | Dark and even, in the shade you pick |
Can you put tint over factory tint?
Yes, and we do it every day. Putting film over privacy glass adds the heat and UV blocking the glass doesn’t have, and it can make the windows darker if you want.
Most of the time, customers with factory privacy glass in the back come to us for one of two reasons:
- Matching the front doors to the back. We tint the two front door windows so they match the factory glass behind them. It’s one of our most common jobs, and it usually takes under an hour.
- Adding heat blocking all around. Film like 3M Ceramic IR goes over the factory glass to keep the whole car cooler, not just darker.
One thing to know: when an officer checks your tint, the meter reads the glass and the film together. Factory glass is already dark, so we pick a film shade that keeps your total reading legal.
Is factory tint legal in Georgia?
Yes. As of July 1, 2026, Georgia law says:
- Front side windows: must let in at least 28% of light on every vehicle.
- Cars (sedans, coupes, hatchbacks and wagons): rear side windows and rear windshield must be at least 15%.
- Most SUVs, trucks and vans: can be any darkness behind the driver.
Each limit has a 3% tolerance. For the full rules, see our Georgia tint law guide.
Which is right for you?
If you’re happy with how your factory glass looks and you don’t mind the heat, you may not need anything. But if your car gets hot, the front doors don’t match the back, or you want better UV protection, window film is the way to go.
We’ve been tinting cars in North Atlanta since 1986, and we only use 3M film. Stop by either shop and we’ll show you the films side by side on your glass.
- See prices: Price Guide
- Book online: Schedule now
- Woodstock shop: 921 Jamerson Rd, Marietta, GA 30066 · 770-592-4265
- Kennesaw shop: 3235 Odeon Way, Suite 220, Kennesaw, GA 30144 · 770-975-2568