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Why does condensation form on your windows and how can you stop it?

Does window condensation bother you? You are not alone in facing this phenomenon. Despite a powerful ventilation system and new windows, it is still possible for condensation signs to appear on your panes. Here are some tips and advice, so that you can better understand this issue.


Condensation is the result of hot and humid air coming into contact with a cold surface. When this warm, moist air meets this too-cold surface, the moisture in it condenses. In the medium to long term, condensation may cause mold and peel off the paint on the edges of your windows.

Energy-efficient windows are less susceptible to this phenomenon, but even they are not infallible. Indeed, high humidity inside the house can only lead to an unpleasant fogging on the inside surfaces of your windows. This is a particularly common occurrence in homes with a humidifier.

From a thermal point of view, windows are the weakest link in the house. Air infiltration around them is a determining factor in the formation of condensation. This is one of the reasons why we often see this phenomenon in the winter.

It should also be noted that, over time, the absorbent strip between your windows becomes saturated with moisture, leading to a loss of efficiency of your double-glazed windows. The sun's rays warm up the air between the windowpanes, increasing the pressure between them and thus creating visible condensation. Before thinking of replacing your windows, the first thing you should consider is reconditioning your double-glazed windows.


The Provincial Association of Quebec Home Builders (APCHQ) suggests you take some simple steps to reduce condensation on your windows.

1- Limit the amount of plants in the house.
2- Make sure your dryer is connected to the exhaust duct.
3- Avoid storing firewood inside your home.
4- Any time you use the kitchen or the bathroom, turn on the exhaust hood's fan or the bath fan.
5- Check the state of your ventilation system and regularly clean the ventilation grids.
6- Avoid taking long showers.
7- Remove mosquito nets during the winter.
8- Avoid completely closing interior window accessories (curtains, blinds, etc.) to encourage the flow of air over the surface of your windows.


An annual insulation inspection of your doors and windows can be useful to prevent water and air infiltration. This will give you a better control of humidity and reduce the chances of fogging on your windows.

Before thinking of replacing your windows, give a call to a Basco expert to get a clear assessment of the state of your double-glazed windows. Our defogging experts will offer you a simple, fast, efficient, and environmentally friendly solution.

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