[firefly123]

never used hot water on glass with wfp is there any chance of some types of glass cracking 

[Clive McDonald]

Yes.
The principles involved are thermal shock and temperature difference.IE even if you use luke warm if you leave it on one spot too long the worst can happen.

Make your first strokes all over ones, be carefull pre nine oclock- and i'm talking a normal plus three or four morning where there may have been a ground frost.

Temps as they are at the moment is a new frontier- we don't know.I'm not working at the moment.

[darren clarke]

most houses should be warm enough to cope with it,  the worse ones are cold cons 

[Clive McDonald]

Not true.

The window you are most likely to break is a single glazed east facing downstairs loo window.On any frosty morning.

[A@R WINDOWCLEANING]

i have been working in -3 -5 for two weeks with hot water done all sorts of windows with no problems yet ,just spray ,scrub then rinse quick, dont spend to long on one window

[geefree]

The outside of the double glazing glass is semi cool,/outside  cold...inside lukewarm   the inside of the double glazed is normal temp with central heating,

Conservatories are an exeption as they dont hold heat and are rarely central heated,

so its only a problem if heating off .

hmm think i will ring all my custis and tell them to leave the heating on.

[windowswashed]

Large windows will absorb the heated water better than small ones. It's the ones with putty and nails in that you have to watch out for. Having said that I've had 2 UPVC units shatter outwards not at the time of cleaning but a week or two later so whether it weakens the glass I have no idea.

I use to be a metalsmith in my previous job and I know that heating up metals and quenching quickly (i.e. in water) makes any welds much more britle than if allowed to cool much slower by controlled means such as immersing in oil or limes or air.

[mileslake]

When  i was younger,windcreen cover had no excess so i and many others didn't bother with de icer, we just threw a bowl of cold water onto the screen. It never ever cracked.
For the last 30 yrs or so they charge a big excess so i just scrape it off...Or if rich i get a can.

[Mr Bungalow]

never used hot water on glass with wfp is there any chance of some types of glass cracking 

Hello Firefly,

I have been told by a company that supplies hot systems to window cleaners.

They say that the majority of the time there are no problems with glass cracking in normal conditions, the only time it would happen is if the glass was already damaged in some way for a crack to happen.

When you use hot water on the windows the temperature is never as hot once it reaches the windows anyway due to extremely low temperatures in winter months such as these.  The temperatures that hot systems reach get reduced very quickly especially once the hose as been reeled out they drop 15degrees every 50metres, so by the time it has gone up your pole there is very little to worry about.

Regards.