Following the replacement of doors or windows, you will sometimes notice an increase in the
condensation on the glass of these new doors and windows. The fact that this condensation did
not appear before the replacement leads you to believe that the product or the installation may
be the cause.
In fact, the increased air tightness of your new doors or windows is partly to explain for this
change. The humidity present in the ambient air, which in the past had been able to escape, is
now kept inside. Therefore, we must understand the exact cause of this condensation in order
to take appropriate action to reduce or even eliminate it. It is for this reason that we have
prepared this informative document, putting together all the pertinent information and
objectives on the subject. We hope that you will find this document useful.
What is condensation?
Condensation will form on windows when the temperature of the surface of the glass (glazing),
sash or frame is lower than that of the humid air surrounding it. The water vapour in the air
changes to liquid when it comes into contact with these cold surfaces. Condensation appears
most often around the edges of the glass since this is where cold air is most likely to infiltrate.
If your windows are subject to condensation, you should know that your windows and their
installation are probably not at fault.
Rather, it is the level of humidity in the house that is the cause, and it is important that you
learn how to control it. Even if you buy the best windows and they are correctly installed, they
will end up showing condensation if the level of humidity is too high.
By humidity, we mean the quantity of water vapour present in the air. You and the members of
your family, and even your pets, produce water vapour by breathing in and out. Even your
indoor plants produce water vapour. We add even more of it to the interior air through our
daily activities, such as preparing meals, taking showers or baths, and washing clothes or
dishes.
Furthermore, water vapour contained in the soil can infiltrate your home through the
basement or crawl space.