why are the windows hot?

[Tinitman]

And don't forget about hidden damage. Hidden cracks, nails, screws, settling of the building, etc.

[EWF]

Heat does not cause thermal shock... you can heat a piece of glass up evenly to a high temperature and it will stay in state. Temperature difference across the surface of the glass is what causes thermal shock.

Yes. That's true. It's the differential that will cause the problem.

It was not explicitly mentioned, but I think the concern is seal failure.

-Howard

[Guest tintjam65]

Temperature difference across the surface of the glass

:onecent

Certainly heating a piece of glass evenly does not cause it to break, but heating unevenly will break annealed glass once the temperature difference between inner surface and edge exceeds 50 degrees F.

200 degrees F. for tempered.

Therefore, root cause is still (absorbed) heat (and shadowing), which produces temperature difference, leading to thermal shock.

Chicken or egg?

[EWF]

Therefore, root cause is still (absorbed) heat (and shadowing), which produces temperature difference, leading to thermal shock.

Chicken or egg?

Good point. Shadowing (we call it partial shading) is the root cause of the differential heating. Typically, it involves a tree, an awning or an adjacent building. Thanks for mentioning that as it's definitely something you need to factor into the glass/film equation.

-Howard

[EWF]

I just remembered something.

AIMCAL produced a superb booklet on this topic (30+ pages, illustrated). It covers everything discussed in this thread and more. We still have hard copies here in the warehouse. Anyone who wants one, just email your request to me at howard@buytint.com and I will mail it right out to you.

-Howard

[Guest vclimber]

Therefore, root cause is still (absorbed) heat (and shadowing), which produces temperature difference, leading to thermal shock.

Chicken or egg?

Good point. Shadowing (we call it partial shading) is the root cause of the differential heating. Typically, it involves a tree, an awning or an adjacent building. Thanks for mentioning that as it's definitely something you need to factor into the glass/film equation.

-Howard

I've been in this argument many times.

Grasp it this way:

Sun comes up and heats the glass and under these conditions day in and day out everything is fine. Point an A/C vent on the top 25% of the window and turn it on and guess what happens? Yes, thermal shock. Why? Temperature difference.

True story... seen it happen many times, even with low SA films. All you need it to cross the tensile strength threshold and glass cracks not due to heat but rather, due to the temperature difference which makes the glass actually pull itself apart.

So as Howard and others mentioned, shadowing can be a cause (which is temp difference), glass thickness can even be a cause (again temp difference), and then you have the mitigators like clam shells, bad glass, nails, settling, etc.

[Guest vclimber]

I just remembered something.

AIMCAL produced a superb booklet on this topic (30+ pages, illustrated). It covers everything discussed in this thread and more. We still have hard copies here in the warehouse. Anyone who wants one, just email your request to me at howard@buytint.com and I will mail it right out to you.

-Howard

Nice publication, still has a lot of valid info in it. Wish they'd publish a newer version though.

[Guest VTD]

If the original poster is even still reading this thread, my personal suggestion would be to hire a reputable professional installer in your area to guide you in finding the appropriate solution for you situation and to install it.

[Guest tintjam65]

Therefore, root cause is still (absorbed) heat (and shadowing), which produces temperature difference, leading to thermal shock.

Chicken or egg?

Good point. Shadowing (we call it partial shading) is the root cause of the differential heating. Typically, it involves a tree, an awning or an adjacent building. Thanks for mentioning that as it's definitely something you need to factor into the glass/film equation.

-Howard

I've been in this argument many times.

Grasp it this way:

due to the temperature difference which makes the glass actually pull itself apart.

No heat, (shadowing, including edge bite), no temperature difference, no pulling apart of glass structure.

Root ^

If the original poster is even still reading this thread, my personal suggestion would be to hire a reputable professional installer in your area to guide you in finding the appropriate solution for you situation and to install it.

If this were the first response, we'd still be this far into the discussion.

[Guest vclimber]

No heat, (shadowing, including edge bite), no temperature difference, no pulling apart of glass structure.

Root ^

There is no such thing as thermal shock without a situation that creates temperature difference. Every day the sun rises... there is no such thing as "no heat" but there is such a situation as no shadowing.