Condensation phenonemon

[Huzzah]

3 x velux windows one always does this on the outside, same pattern every night. If cold it's frozen otherwise just moist. Looks like a toilet seat, Mrs H has named hi Kenny. (Looks quite spooky in the moonlight.




Any idea why, only window that does it, same pattern every night.

[b14]

Are all the others fully frosted over? My guess would be some kind of airflow of warm air from above that defrosts part of it

[Peanut Gallery]

How hard would it be to clean the window? - The first bit of my car windscreen to mist up is where a sales sticker had been applied many moons ago, you could not see any residue etc once the windscreen heated / enough air was blown over it. I was trying to clean something else off and have since removed the bottom half of the stickers effects, so maybe cleaning it with meths might change the shape, if so you know what caused it.

[dmsims]

Peanut Gallery said:

How hard would it be to clean the window?

You can flip them round and lock the position so easy to clean the outside from inside

[POIDH]

Huzzah said:

Any idea why, only window that does it, same pattern every night.

Are they windows which have argon or similar gas? If so I bet this one has lost its gas or has a slight leak - pattern is the cold bridges from the edge of the pane and frame.

[netherfield]

There was a recall on Velux windows a few years ago, could be 10 or so, both were replaced under warranty, over the last 2 years a pattern appears on one at certain times of the year, very symmetrical, a circle in a circle with various dots, size of a football, looks like a trade mark or such, goes away as quick as it appears.

[cliffords]

All my conservatory roof windows do that . 12 pieces same shape on every one .Two years old .

[Little Lofty]

Send a picture to Velux technical, they are a very helpful bunch so will know what it is.

[cliffords]

My conservatory roof now. No heating in here just now

[markymarkthree]

The sun dun it.