New double glazing and external condensation

stagey_2

Hi - my mother has had new double glazing windows installed a few weeks ago. On one of the windows condensation is appearing on the outside of the glass - but not on the other new windows. Sometime's it lasts for several hours. She is becoming very concerned that there may be a fault with the glazing and she is not getting much joy from the installer - I must confess I get a little condensation on our much older windows inside, but not on the outside. Can anyone enlighten as to whether or not external condensation could be a sign of a faulty installation. Many thanks

BertieUK

Could it not be similar to what happens to your car windscreen when its parked in the driveway, simply dew?

Just a thought

Regards
Bob

I can hear my Science teacher saying to you.

Almost all objects with temp greater than absolute zero (and all have that) give off blackbody radiation in proportion to their temperature. But they also receive blackbody radiation from other objects. Or to put it another way, objects are exchanging heat with each other until they all have the same temp.

stagey_2

Yes indeed! that was my original response to my 89 yr old mother - but they get very much more concerned about such matters the older they get - nothing else to worry about much, you see. It didn't happen with her older (much) double glazing tho, that is the problem for her.

Avoriaz

External condensation is common and nothing to worry about. In fact it demonstrates that the double glazing is doing its job in preventing heat leaking out of the window.

http://www.pilkington.com/Europe/UK+and+Ireland/English/Building+Products/forHouseholders/Frequently+Asked+Questions/Householders+FAQs+-+General.htm

stagey_2

thank you so much!

steppevos

The double glazing is working so well that the outside pane cools down (because of blackbody radiation at BertieUK explained) and doesn't get warmed up from the inside. The outside air also cools down and reaches saturation and excess waterdamp is deposited on cold surfaces (as dew on grass ;-) and condensation on your mom's window).
I am under the impression that it is happening more than last year as we had it this week several times even on our older double glazing windows.

LadyDee

I too have been experiencing this on the outside of new double glazing. It doesn't worry me unduly other than it does take a while to clear and I'd prefer to be able to see through the windows.

Is there anything I can use to clean the windows which would encourage the windows to clear more quickly?

DaftyDuck

Washing up liquid - diluted, but not then rinsed off with water will help. You can use an old washing up bottle with a couple of drops in it, fill it with water, and simply run it along the top of the glass.

I have used dishwasher rinse-aid on my conservatory roof (helps the bird do-do wash off in the rain), but that may be a bit strong.

maninthestreet

Try Rain-x Anti-fog.