WFP, Cold Water, Hot Day, Crack Glass?

Has this ever happened to anyone - has a window pane ever cracked on someone using a WFP pole with cold tap water on glass that has been sitting in the sun on a hot day?

This has never happened to me as this is my first year and we have yet to have really hot days but it has happened to me when washing my car last year. The car was sitting in the hot sun for a few hours, I went to do a pre-rinse before washing and the windshield cracked. Can this happen on house windows using a WFP?

You are talking about thermal shock.
YES… This can happen on a day that’s 170 degrees temp and the waters temp is 32 degrees. Maybe.
Can you imagine how many windows would crack on a hot day because water ( or rain) got on the hot glass?
Being a glazier I have responded to supposedly " thermal shock" cracked glass calls and always was never the case.
Building settling was the lead, and birds flying into the glass was second,
Amazes me how people can see a crack but miss the big ole splotch of bird from crashing into the window…
While I will not say its a impossibility thermal shocking from a wfp is the least of your worries…

Its usually the other way round. ie: too hot water on glass below 32f. Many a windshield has ended its life this way from people thinking that boiling water is a great way to get rid of the overnight frost.

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^ this

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This is true.
I would think that those cleaning windows in below freezing weather would be using water heaters for their wfp’s wouldn’t have them set above 90 degrees.
Yet many moon ago while in my youth I did crack my 65 VW bugs windshield in sub zero weather thinking to do a quick defrost with boiling water.
Ahhhhhh… The Youth

Temperature differential can lead to stresses in glass. Air conditioning in summer & heating in winter inside the building can also add to diffential when cleaning the outside. It can be viewed quite commonly in hot climates without water by seeing where they have put darkened film on half the glass leading to heat differential between the top & bottom leading to stress cracks.

Very useful post. Thanks

I think it’s time to bring this thread back to life. I’m leaving money on the table because of the cold temps. I’ve got a list of monthly wfp jobs just waiting to be cleaned. I’m looking into the Eccotemp L5 portable propane heater to put after my backpack.

Does anyone know what temperatures are involved in thermal shock of glass? I’ve heard of UK wfpers going as low as -12 C/10F with their systems. Does anyone here have any experience and insight?

Joshua Adriance
Pure Water Window Cleaning

There is another thread going on, almost identical, with more info and comments.