My bathroom has a ceiling window (nothing above it) that has a lot of condensation when it's cold, and drips inside. A builder checked it out as we initially thought there was a leak when it's raining, he said it's just condensation. Seems to be the case as the dripping does occur when it's cold and not raining. But it's very annoying so I was wondering what can be done to stop the dripping. The window does not open, there is a small separate fan (operates when light switched on) and no other windows just a door. Even if the door is open and we haven't showered yet etc there is still some dripping during cold weather. Any advice on some kind of insulation / treatment for the window would be greatly appreciated.