Many new owners of PVC windows often complain about drafts from the newly installed windows, especially in winter.
Even quality installations, when everything is foamed, insulated and covered with plaster, often produce what feels like a cold shower. Well, first, PVC windows are not completely sealed – that’s a myth. If you put a mouse in a jar and screw a tight lid on, the mouse will suffocate and die. That is exactly what happened to early PVC window owners when the latter first appeared. That’s why Germany – the innovator in PVC windowing with brands like Rehau and KBE, enforced a standard which requires at least 20% of air to pass trough said windows. So they don’t really seal you off from the outside. But draft are not acceptable! So if you feel them, take a look at your windowsills. Old brick houses tend to have very deep windows with big window boards, and that is exactly the reason of your discomfort. The radiator is usually even more distant from the glass, and the window niche forms a still air zone, which is not heated by the radiator, but is chilled by the cold glass. And then convection makes its job, and the cold breeze goes into the room. So this is not cold air from the outside, this is the inside air which was chilled by the cold glass. So, what should you do? Obviously, try to warm up the cold air in the window niche. To do that, cut a hole in the window board above the radiator. Then insert a ventilation grill with strips angled towards the window. This will direct warm air to the window glass, and the cold shower should seize. And another point. If you newly installed windows condense water, and black mold forms at the sealings, check your ventilation. Clogged ventilation may cause high humidity, so plumb it yourself or call up chimney cleaner service.