Dark and cool are not the same thing.

Sunlight is three things

What comes through your window is roughly half infrared (the part you feel as heat), a little under half visible light (the part you see), and a few percent ultraviolet (the part that fades your dashboard and damages skin).

Here's the point: the darkness of a film describes what it does to visible light only. VLT — visible light transmission — is a measure of shade, not of heat. A film can block a great deal of visible light and comparatively little infrared, which is exactly what cheap dyed film does. It looks like it should be cooler. It isn't, much.

Which is why 5% limo tint can be hotter than legal ceramic

This surprises people every time. A cheap 5% dyed film makes the cabin dark and blocks a modest share of infrared. A quality 35% ceramic film lets you see out comfortably and rejects far more of the heat. Same sun, same car, and the legal one wins on the thing you actually cared about.

Dyed film works by absorbing light, and absorbed energy becomes heat — some of which then radiates into the cabin anyway. Ceramic particles reject infrared rather than soaking it up. Different mechanism, different result.

The number that matters: TSER

If you want to compare films honestly, ask for Total Solar Energy Rejected. TSER accounts for infrared, visible, and UV together — the whole solar spectrum — and it's the closest single figure to "how much cooler will this actually be."

Be a little wary of headline "IR rejection" percentages in advertising. They're sometimes quoted at the one wavelength where a film performs best, which is technically true and practically meaningless. TSER is harder to game.

What tint can and can't do about heat

It can substantially reduce the solar heat coming through the glass, take real load off the air conditioning, cut the searing feeling of direct sun on your arm, and stop the dashboard reaching the temperatures that crack it.

It can't keep a car parked in full sun genuinely cool. Heat also arrives through the roof, the body panels, and the windshield, and a closed car in July is going to get hot regardless. Tint means it gets less hot and recovers faster once you're moving — not that it stays comfortable.

What this means for what you buy

Pick your shade for how you want the car to look and how much privacy you want, and pick your film for how much heat you want gone. With ceramic those are genuinely separate decisions, which is why so many people end up perfectly happy at a legal 35%.

See the shades in the tint viewer, compare grades in ceramic vs. carbon vs. dyed, or book ceramic tint with us.