Very often during the cold season you may notice water droplets on your windows and sliding glass doors inside your house, they can also freeze and form an icy crust. You will probably think that your windows/doors are faulty and in need of repair, but don’t jump to conclusions. Let’s try to understand why condensation occurs on windows.
What is condensation?
There are water droplets that appear when water vapor (an invisible gas) becomes colder and turns into a liquid. Cold air contains less moisture than warm air. As the temperature drops, the cooled air can no longer hold moisture and condenses on the cooled glass surface, leaving water droplets. Thus, when it’s cold outside and your home is warm, condensation can appear on your windows from the inside.
What causes condensation on windows and doors?
There are several reasons why condensation can occur on your windows and sliding glass doors:
1. We’ve already mentioned temperature differences. When warm, moist indoor air collides with the cooled surface of a window or door, condensation forms.
2. A second possible cause of condensation is high indoor humidity (such as during cooking, showering, or laundry). The higher the humidity level in the room, the more likely condensation is to form.
3. A third possible cause is poor ventilation of the room. If a room is poorly ventilated, moist air cannot escape, causing it to build up.
4. Poor insulation or damaged window/door seals can contribute to cold air infiltration and increase the likelihood of condensation.
Are windows and doors the cause of condensation?
Windows/doors themselves are not the cause of condensation. Their cooled surface becomes a place for condensation of water vapor.
Do curtains and blinds cause condensation?
Tightly closed curtains can restrict air circulation, which can contribute to the build-up of damp air and therefore increase condensation. If curtains are damp (for example, after washing or due to high humidity in the room), they can add extra moisture to the air, which also increases the likelihood of condensation.
What causes condensation on the inside of a double pane window?
The interior panes can be cooler than the air in the room. When warm, moist air comes in contact with the cold glass, it cools down and the moisture from it condenses. If condensation has formed between the panes of glass, it may indicate that the window’s airtightness has been damaged. This means that air can pass between the panes, which reduces thermal insulation (more on this in the article “Window glass condensation: When is it time to replace?”).
Is there anything I can do to my windows/doors to eliminate condensation?
Yes, if you have single glazed windows, you can replace them with double glazed windows. Double glazed windows can help to maintain a more stable room temperature, which in turn can reduce humidity levels and reduce the chance of condensation.
What is humidity?
Humidity ¬ is the amount of water that is in the air. Humidity comes in absolute (how much total water is in the air) and relative (the percentage of how much moisture is in the air compared to how much water it can hold at a given temperature).
Where does indoor humidity come from?
People breathing, cooking, showering, washing and drying clothes and leaks in pipes, roofs or windows/doors can cause excessive moisture in a room.
Can windows/doors help control indoor humidity levels?
Only by opening them to regularly ventilate the room. Otherwise, windows and glass sliding doors can only serve as indicators of excessive humidity in the room.
Does condensation depend on the season of the year?
In winter, cold air causes condensation of warm, moist air, while in summer, high humidity and air conditioning can cause condensation on cold surfaces. Condensation also depends on the climate, so in areas with a more humid climate the level of humidity is higher, which increases the likelihood of condensation, especially during temperature fluctuations.
What is the recommended indoor humidity level?
During the cold season, we recommend maintaining a minimum humidity level in your home that is safe for your health. This measure will help you get rid of excess moisture and the spread of mold.
If you have questions/are unsure about the serviceability of your windows/glass sliding doors, you can contact us for advice.