All of our windows vapour. They have been replaced about ~10 years ago.

From outside the house got ~10 cm dryvit. The house was built out of "grey silicon" bricks.

We have heating with Co-firing, with buffer tank.

We always heat up every room, every time.

Question: what could the cause of the vapouring be?

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UPDATE: maybe the windows are out of argon? or never had any? how do I know?

UPDATE#2: The water is inside the house, I can touch it with my finger.

  • Is the water inside the window, between the panes? Or can you touch it with your finger? – iLikeDirt Dec 11 '15 at 5:59
  • I updated the question, thx – LoukiosValentine79 Dec 11 '15 at 6:10
  • LOL. There are at least 4 things in this question that I don't understand. "Dryvit"? "Grey silicon bricks"? "Co-firing"? Bottom line, any window will collect condensation if the interior humidity is too high. It's important to vent moisture from bathrooms, etc. during cold weather. I've seen high-quality windows in fairly new homes completely rotted away due to disregard for moisture. – isherwood Dec 11 '15 at 15:28
  • Dryvit is a brand of EIFS, an exterior wall covering. I'm not familiar with "grey silicon bricks" specifically but this undoubtedly refers to some type of masonry block. – iLikeDirt Dec 11 '15 at 15:47

In a nutshell, the cause is excess humidity indoors when it is cold outside. Your windows are not defective, but they are not the kind of super-high-performance windows that would be warm enough not to attract condensation. You should investigate sources of moisture indoors. Usually houses are dry in the winter, not wet, so this is a bit unusual. Do you use a humidifier? If so, turn it down.


When the glass gets cold enough it will draw moisture from the air, just like condensation on a glass of iced water. This doesn't imply that the windows are bad, just cold.

Modern buildings are sealed much better than old older buildings. This is generally a good thing, but one of the problems is that it is harder to get rid of excessive humidity.

This condensation can cause problems such as mold, mildew, and/or damaged paint.

To help with this you need to reduce the humidity inside your home:

  • Use exhaust fans to vent steamy air during (or after) running the shower
  • Similarly, if boiling water on the stove, use a hood vent (or open a window)
  • Make sure your clothes dryer's vent hose isn't leaking warm moist air into your house.
  • If these aren't sufficient, buy a dehumidifier

A relatively inexpensive dehumidifier simply sits in the corner and collects water from the air. The water collects in a reservoir, which you have to empty regularly. However, I would highly recommend installing a drain hose. It's amazing how much liquid can be gathered in just a few hours!

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