How much ventilation do windows require?

Lizzybop

Aaarrgghhhh!! My ongoing windows issue has reared its ugly head again. The overnight temperatures have dropped on a few occasions over the last week or so, and even with my windows left slightly open (you know when you can have them open a crack but still locked so no-one is getting in??) Still have condensation.

I take every possible measure to limit moisture within the home including but not limited to, extractor fans when cooking and in bathroom, no drying clothes on radiators etc. etc.

I have spoken to an expert in the home energy field and they have suggested that my windows haven't been installed correctly. The window company don't want to know. They just blame us - tell us it's modern living. No-one I know takes as much care as I do to limit the moisture in my home.

I saw one of those consumer programmes on t.v. once - you know the ones with Dominic Littlewood, where some flats in the same block all had the same problem that I seem to have. They all got told the same thing as I do, that it was their fault. The programme got in a surveyor and removed one of the windows. Turned out it had been incorrectly installed, so they had all the windows re-installed.

I can't afford to pay a surveyor to come and do that for me, and for all the rooms in the house it does happen in, it never happens in the kitchen, which doesn't really make sense.

So I guess I will just have to build in an extra ten minutes into my morning routine, to go round all the bedrooms and mop up the rivers of water in the morning.

Oh well, thank you for reading if you've got this far. It has helped to write it all down.

Any surveyors out there.......???????

BitterAndTwisted

Windows don't cause condensation. Too much moisture in the air inside hitting a cold surface does that. If you really are ventilating adequately the question you should be asking yourself is: where is that moisture coming from? Because it's certainly not coming from the windows.

**professor~yaffle**

You can get moisture blocks from Lakeland, I think, which stand on the windowsill and absorb the condensation so that hopefully you don't get puddles of water on your sills in the winter.

I have this problem, too. I also have a weirder one, where we get condensation on the outside of the glass! My flat is definitely warmer than outside, so not sure what's causing that :rotfl: Must be the sea air!

pollypenny

We have a moisture problem in the bedroom, too. OH is always so hot!

We use stuff from B&Q which helps.

However, the windows are 25 years old now and we are wondering if new ones, with improved insulation will work.

Gloomendoom

**professor~yaffle** wrote: »

I have this problem, too. I also have a weirder one, where we get condensation on the outside of the glass! My flat is definitely warmer than outside, so not sure what's causing that :rotfl: Must be the sea air!

Which rather proves the point that more ventilation probably isn't the cure for condensation on windows. You can't get much more ventilated than outdoors.

Fluff15

We have this problem! We use these: http://www.amazon.co.uk/151-Products-LTD-Interior-Dehumidifier/dp/B005MZ1EJE/ref=sr_1_1?ie=UTF8&qid=1380033574&sr=8-1&keywords=condensation

They don't get rid of it all, but they definitely help. We've also got an old towel we use to wipe the rest of the condensation.

We did have a specialist come round once as instructed by the landlord, and he suggested installing an extraction fan into the side of the flat, which had a sensor in another room which set it off when the moisture levels get too high - but this was expensive.

Our condensation is caused just by us living in the house. Breathing expels moisture, as well as cooking etc, which then gets trapped in the house and gathers on the cold surfaces. A dehumidifier wasn't any good as the moisture was only gathering when we were in the house. It doesn't happen in our kitchen either, but our extractor hood is very good and overall, the temperature in the kitchen is always much higher than the rest of the house, so I think it evaporates better.

tyllwyd

If the windows are left open at night, doesn't that mean that the double glazing is not being given a chance to do its job? I'm wondering if the warm air from the house is meeting the cold air from outside and condensing on the window. How about, as an experiment, leaving the windows closed overnight and heating the house a little bit warmer. If it is still getting condensation overnight, and you are certain that the house is well ventilated etc during the day, then I'd look into getting a double glazing repair man. Otherwise, its a waste of time (and energy) having double glazing if you never close the windows!

harrys_nan

**professor~yaffle** wrote: »

You can get moisture

I have this problem, too. I also have a weirder one, where we get condensation on the outside of the glass! My flat is definitely warmer than outside, so not sure what's causing that :rotfl: Must be the sea air!

We have this as well and live on the coast,:rotfl:

WTFH

Lets see...
Windows open all night - I'd expect them to have moisture in the morning.
Windows open when it's raining - I'd expect you'll get moisture in then

Plenty of things increase the humidity and moisture levels in a house, most of them are due to the people in the house, not the people who put the windows in.

WestonDave

Re the outside condensation - entirely possible and expected if you have very efficient double glazing.

If you think about it, your car gets condensation on the windscreen most mornings in winter because the windscreen glass is a cold surface. Glass cools quickly as its a relatively poor insulator. So if your glass isn't getting heat from inside because the double glazing is efficient, its going to cool and a cool surface causes moist air (as by the sea!) to deposit the water vapour it holds as condensation. Cold air cannot hold as much water as warm air so as air cools (in this case in contact with the glass) it dumps the water it can't hold any more - voila condensation.

If you want to cure condensation you've two basic options - reduce the moisture in the air so it won't reach "dew point" (which is the combination of relative humidity and temperature at which it dumps water) or keep the temperature up so it won't reach dew point.

Reducing the moisture means either using a dehumidifier to get the water back out of the air, or swapping warm wet air from inside for cold dry air from outside. (This gets a bit hard to understand but even if its raining outside the air is probably holding less moisture than your warm inside air - bring that air in from outside and warm it up and you have warm dry air). However most people are worried about energy bills so don't want to let all their nice warm air go out. A dehumidifier is therefore probably the better option and these days are relatively low energy.

Heating the house further can help, but cold surfaces like windows will often still be vulnerable. Provided the moisture is removed and disposed of then its not a problem in itself if its just the glass as mould won't grow on wet glass if its wiped up daily. Don't however wipe the window down with a towel, and then put the towel on the radiator to dry because guess where that water will be back to next morning! Either use something disposable or one of the Karcher window vac type things or if its a fine day a towel that you put outside to dry.