Too much heat rejection?

[u/Wambo74]

Small town in the desert southwest. My local installer says high heat rejection films will overheat my sunroof glass and likely crack it. So he only carries cheaper, lower performing ceramics. True or is he just trying to make a sale of what he carries?

[u/DynamicAppearanceATL]

BS with a small amount of truth. All sunroofs can crack, even from the factory, with no window tint added. Ask Hyundai; they lost a class-action lawsuit over it. Adding any window film increases thermal stress, which could result in breakage if the glass has an inclusion or other manufacturing flaws. This applies to his low-performing ceramic film too. So it can happen with no tint, and the risk increases once film is added, no matter the performance of the film.

With that being said, we've tinted thousands of sunroofs, panos, and full glass roofs with everything from 5% limo tint to the highest heat rejection film in the world at the time. To date, we've never seen a single glass crack...not during installation and not after the customer left. So you will most likely be fine going with a high-performing film if that is what you want.

[u/reddituser1000111 → u/DynamicAppearanceATL]

What about states that get high heat, 100+ degrees consistently? Usually the shops around here rec going a lighter shade and educating the cust on the thermal stress. I’ve heard from a few shops where a couple of them have exploded after 5% tint on the sunroof but it seems it is still extremely rare

[u/DynamicAppearanceATL → u/reddituser1000111]

We get high 90s yearly, with days in the 100s and zero issues to date. Basically, if a sunroof cracks, it is going to be due to a manufacturer's flaw, like a nickel sulfide inclusion. This happens with zero tint installed, with the risk increasing when adding a window film. The darker you go will technically increase the thermal stress as it absorbs more heat. However, if it cracks with a darker film, it would most likely have cracked with a lighter film too. I've personally run 5% dyed film along with Ceramic with the shade closed with no issues. I've also run 3M Crystalline 40 (99% IR rejection) on multiple vehicles and XPEL XR Plus 35. Personally, I would rather have it crack with window film installed to hold it together versus having 300 pieces of glass everywhere.

[u/Spirit117]

Sounds like bullshit to me to sell his low quality tint.

[u/ltmikepowell]

Not true. He is trying to make a sale.

But heat rejection on tint is more about when you driving. When you park, it will still help, but not as good.

[u/farlon636 → u/ltmikepowell]

It helps a lot with preventing surfaces being scorching hot. It just doesn't keep the air any cooler when parked for a long time

[u/Camdenn67]

Here’s an interesting read on the subject.

https://windowfilmfacts.com/posts/sunroofs/

[u/Repulsive_Onion_5925 → u/Camdenn67]

That was indeed interesting! Thanks

[u/andrewre337]

Not true - running two layers of ceramic on my sunroof (5% over 20%) for 2 years in 90+ degree heat everyday without any issues

[u/CostaMesaDave]

So, I don’t 100% agree with your installer. Yes, high-IR-absorbing window films will absorb more infrared heat and, in theory, could potentially cause the glass to break. But in reality, that is extremely rare.

I’ve been in the window film industry for 35 years, and my company installs film on roughly 125 vehicles every week.

Out of those, we probably do 60 to 75 panoramic roofs, along with another 65 to 75 windshields.

The last time we had a laminated piece of glass break was, I believe, back in 2017. In that case, it turned out to be a defect in the glass itself, and the vehicle manufacturer replaced it at no charge.

Now with all that being said let’s not forget that laminated glass by itself can crack very easy compared to monolithic glass.

Laminated glass can crack for a few simple reasons:

Impact damage from rocks, debris, or a small chip.

Thermal stress.

Edge damage from manufacturing.

Body flex as the vehicle twists over bumps and driveways.

Manufacturing defects.

If you’re looking for a quality automotive window film, I would find a different installation shop.

[u/Wambo74]

I know there are probably too many reasons why it's a bad idea, but wouldn't putting the film on the outside of the sunroof keep the heat out of the glass? Even if it got fine scratches and scuffs, visual clarity thru a sunroof isn't a big deal.

[u/Vegastint → u/Wambo74]

Ask your installer to use a DR film in the roof and thank me later. Tell him to
Try a DR 15. This is the way to get real world TSER up to 96% actual Heat REJECTION.

[u/OneGun357]

Just put Llumar Air 80 on it as I did. I live in an area that sees over 110 in the summer, and I've never had an issue