The kind of film on your windows decides how it looks, how much heat it keeps out and whether it fades. There are five main types of automotive window film. This guide explains each one, shows where the three 3M films we install fit, and tells you how to compare spec sheets without getting misled.
The five types of window film
Dyed film
Dyed film gets its dark colour from layers of dye. It’s the cheapest kind of tint. It gives privacy and has a flat, non-reflective look, and it doesn’t interfere with phone or GPS signals.
The trade-offs are big. Dyed film keeps out little heat, and the dye breaks down in sunlight. Over a few years the film fades and turns purple. We explain why on our page about tint turning purple.
Metallized film
Metallized film has tiny metal particles in it. The metal reflects heat, so it keeps out more heat than dyed film, and it doesn’t fade the same way.
The metal also causes problems. It can interfere with radio, GPS, cell signals, Bluetooth, toll transponders, keyless entry and tire pressure sensors. It has a shiny look, and Alberta doesn’t allow reflective film on any window. We don’t install it.
Carbon film
Carbon film uses carbon particles instead of dye or metal. It keeps out more heat than dyed film, doesn’t fade to purple and doesn’t block signals. It has a deep matte-black look.
Carbon keeps out less heat than ceramic film. It’s the right choice when privacy and price matter more than heat. 3M’s carbon film is 3M Colour Stable.
Ceramic film
Ceramic film uses tiny ceramic particles to absorb infrared light, which is the part of sunlight that carries heat. It keeps out much more heat than carbon, it stays clear to look through, and it doesn’t block signals.
Quality varies a lot between brands and product lines. Some budget ceramic films perform little better than carbon, so it’s worth checking the spec sheet. 3M’s ceramic film is 3M Ceramic IR.
Multilayer film
Multilayer film stacks a large number of very thin layers, each tuned to block part of the infrared range. It keeps out a lot of heat while letting visible light through, so it works in light shades. It costs the most, and only a few manufacturers make it. 3M Crystalline is built this way, with more than 200 layers according to 3M. Read more on our 3M Crystalline page.
Where the 3M films fit
We install three 3M films. All three are non-metallic, so none of them interfere with electronics. These figures are from 3M’s own product bulletins.
| 3M Colour Stable | 3M Ceramic IR | 3M Crystalline | |
|---|---|---|---|
| Type | Carbon | Ceramic | Multilayer |
| UV blocked | 99% | 99.9% | 99.9% |
| Infrared rejected | 44% to 53% | 95% | 97% |
| Total solar energy rejected | 39% to 47% | 59% to 66% | 34% to 59% |
| Shades | Light to very dark | Light to very dark | Light only |
| All windows, from | $599 | $799 | $999 |
3M measures infrared rejection at 900 to 1000 nm. Total solar energy rejected (TSER) counts visible light, UV and infrared together, so darker shades score higher on it.
The table shows something that surprises people. Crystalline’s TSER looks lower than Ceramic IR’s, because Crystalline comes only in light shades and TSER rewards darkness. What Crystalline does is block almost all the infrared while letting the light in, so the cabin stays cool without dark glass. If you want dark glass and lots of heat rejection together, Ceramic IR is the better fit.
How to compare spec sheets
Tint brands publish numbers in ways that make their films look good. A few rules keep the comparison fair.
- Compare at the same shade. A film’s darkest shade almost always posts its best heat numbers. A claim made at 5% doesn’t tell you how the 35% shade performs.
- Check how infrared was measured. A figure measured at a single wavelength will be much higher than one measured across the whole infrared range. Two brands’ “IR rejection” numbers often can’t be compared.
- Use TSER for overall heat. It’s the closest single number to how much cooler the car will feel, as long as you compare at the same shade.
- Look for missing numbers. Some brands don’t publish heat figures for their cheaper lines. If a number is missing, you can’t compare that film on heat.
Our brand comparison puts 3M, XPEL, LLumar, FormulaOne, SunTek, Rayno, KAVACA and Johnson side by side using one measurement method.
Shade and Alberta law
Darkness is measured as VLT, the percentage of visible light that gets through. A 5% film is very dark and a 70% film looks close to clear.
In Alberta, the shade only matters on the rear windows, and there it’s your choice. The rear side windows and the back glass can be any darkness, as long as the vehicle has outside mirrors on both sides. The windshield and the front side windows can’t have any film at all, light or dark, unless you hold a medical exemption permit. Our Alberta tint law guide covers the details.
Which type to choose
- For privacy on a budget, choose a carbon film such as 3M Colour Stable. Skip the cheapest dyed films, because they fade.
- For a cooler cabin with dark windows, choose a ceramic film such as 3M Ceramic IR.
- For a cooler cabin without dark windows, choose a multilayer film such as 3M Crystalline.
Every 3M price is listed in one place. See the price list.