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condensation on double glazed windows

Postby pry020112 » Mon Dec 08, 2008 11:00 am

hi can anyone help i get condensation ang mould on all my windows through out my house. it seems worse this year im getting puddles on my window seels. my windows dont have vents so i try to leave the windows open a little bit but this does not seem to work.thanks
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Postby plumbbob » Tue Dec 09, 2008 12:16 am

Keeping windows open in the summer may work well in keeping humid rooms such as bathrooms and kitchens dry because the outside air is dryer than inside and allowing the air to circulate evaporates any water lying about in the room.

In the winter months outside air is cold and damp. Just looking at my humidity meter now, tells me that outside air contains more moisture than inside air so letting it in is only going to bring in more water than will be removed.

Another point, incoming air will make the area around windows colder and therefore condensation is even more likely to develop.

You could reduce the amount of water vapour in the room, but that is pretty difficult unless you stop breathing and doing anything that produces steam.

Really the only effective way to reduce condensation is to make the window warmer by having double glazing and a warmer room. This is the main reason why radiators are placed under windows.
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Postby nitro23456 » Tue Dec 09, 2008 10:00 am

do you dry any washing on your rads? told my wife off for this yesterday!!
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Postby Amberflame » Fri Dec 12, 2008 3:49 pm


I had the same problem with [u]one[/u] of my windows and it was because the radiator under the window needed bleeding. It is working fully now and my window has dried up. You just need to keep your house at a good temperature during the winter months to avoid this i think.
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Postby Perry525 » Fri Dec 12, 2008 8:18 pm

When we write about humidity it is always relative humidity.

Saturated air, that is to say air at a temperature of 30C holds 30 ml of water per cubic metre and registers at 99% humidity.

Saturated air at 20C hold 18 ml of water at 99% humidity.

Saturated air at zero C holds 5 ml of water at 99% humidity.

And so on.

From the above you will note that while the air outside may be saturated with water while its outside, once it comes in it is dry compared to the air already in the home.

As its temperature goes up the percentage of water goes down.

That is why we open the windows to dry the home - as in most instances, not always, the air outside is drier than inside.
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