I have had this a few times and the customers have claimed on their guarantee and got new glass installed.It happens when the cold water that hits the outside the air in the sealed unit then causes condensation due to a small gap in the unit.
wayne , would not do that. have you not seen all the how much i earn a day postsno! no! no! keep them well awaysimbo
Ask her what happens when it rains
I'm not talking about upvc double glazing.I was talking mostly about wooden frames on old houses or new barn conversions.It goes in the top or down the inside when doing the pane above.Really annoying to have to get a long pole with a squeegee on just for those windows.