Thanks, but it's not the Alu dust, this is fine paper dust up to 1.5mm long and small grey gritty wood ash dust from the wood stove. It's on both panes of glass in the cavity and seems attached by static; however it does move around the cavity. The dust was not present when the windows were...
We're sure it's on the outside. You can run a finger across the moisture and leave a trail, it's definitely on the outside. Although I'm sure it won't long before the leaky units are misting up in the 'sandwich'.
Thanks.
I think the windows are low E rather than K-glass.
The really strange thing is that even with all the windows open on a warm, breezy night the glass is still steaming up, on the inside of the open ones too.
The rest of the house (walls, single glazed windows, doors etc) is...
We had new double glazing fitted this summer, ever since it's been subject to frequent external condensation, four days in the last six; it's averaging at one day out of every two and sometimes starting late afternoon, early evening and lasting until mid morning. Both upstairs and downstairs...