It has come as a surprise that the windows at Ridgeway get condensation — on the outside. It probably should not because this effect on high performance windows is well documented.
The real problem is that the condensation reveals every spot of dirt and every fingermark on the window. I will have to get out there and wash them. But after an hour or so they are crystal clear again: the washing can be put off.
Pilkington, the glass maker, explains:
The choice is between some condensation now and then ...or higher heating costs, a higher environmental load and poorer indoor comfort.
It shows that not enough heat is passing from the house through the glass to prevent condensation. They are doing the job we paid for. It is also serves as a reminder to get the windows cleaned which is also a good thing.