Marks on inside of double glazing

[annem]

Marks keep appearing on the inside of the double glazed unit of one of the bedroom windows. To me, the marks look like an impression a textured cloth would leave. It seemed to appear when we had the cold spell, but it is not condensation. Sometimes the window is completely clear.

It is a small bedroom and a large son sleeps in it so from time to time we do get condensation on the window overnight.

Condensation was a big problem in the same bedroom a while ago, but the problem was solved when I bought a dehumidifier.

Any ideas anyone?

 

[diymadhelpout]

was the window fitted with a vent? also how old are the windows?

 

[annem]

The windows are about 10 years old, and don't have vents fitted.
The other windows are fine, it's just the smallest bedroom which has the problem at the moment.

 

[diymadhelpout]

if the marks are definatly on the inside of the glass then the seals have blown i think. If you want to fix it i think you would have to get a local glazier or window firm in.

 

[annem]

Yes it looks that way.
OH priced up a sealed unit last week, just debating whether to replace the whole window so I can get to clean it myself - depends on the cost.

I can't understand why the marks are intermittent. If the seal had broken I would think there would be marks there all the time. I'll try to get a photo next time I notice it.

 

[diymadhelpout]

then again it might just be the humidity in the air as you said the dehumidifier worked.

 

[annem]

I can't understand why marks appear on the inside though. The marks are there now and its a sunny but windy day.

 

[freddiemercurystwin]

The marks/finger-smudges were probably made when the unit was being assembled and slight variations in the humidity/air conditions etc cause them to be noticed at certain times.

 

[annem]

Thank you both for your input.
It looks like we'll have to bite the bullet and replace the unit then.
Cheers