Condensation on windows is caused by warm, moist indoor air cooling against the cold glass, leaving the moisture behind as water droplets. The cause is therefore a combination of too much moisture in the home and a cold window surface. You solve it by removing moisture through ventilation and, where necessary, reducing the humidity with a dehumidifier, for example.
Direct answer: Condensation on windows comes from moisture in the indoor air that condenses on cold glass. Limit the source (cooking, showering, drying laundry), ventilate regularly and reduce the humidity if necessary. If it continues to return structurally, a dehumidifier can help lower the moisture level, but it does not replace ventilation.
Why does condensation form on windows?
Air can contain a limited amount of water vapor, and warm air can hold much more than cold air. When warm indoor air hits a cold surface, such as a window in winter, that air cools locally and can no longer hold all the vapor. The excess turns into small droplets. This is why you see condensation especially in the morning and on the coldest windows, and usually at the bottom in the corners.
Moisture enters the home every day. A family brings it in through cooking, showering, breathing and drying laundry. Without sufficient ventilation, that moisture remains inside. How humidity relates to a pleasant indoor climate can be read in our article what temperature and humidity are ideal in the home.
Is condensation on windows harmful?
Occasional condensation after showering is often harmless, as long as you wipe it away and ventilate the room. If it becomes structural, the moisture can seep into window frames and walls. According to Milieu Centraal, too much moisture can cause mold on walls and ceilings, and can damage paint and woodwork. So if you often have wet windows, it is therefore better to tackle the cause instead of mopping up every morning.
Have you already noticed a musty smell in the home? Then the moisture problem may be broader than just the windows. Read then why your house smells musty and what you can do about it.
What can you do immediately against condensation on windows?
Start at the source and with the air. Below are the measures that yield the most in practice.
| Measure | Why it works | Note |
|---|---|---|
| Ventilate after showering and cooking | Immediately removes moist air | Milieu Centraal advises 20 to 30 minutes after showering, no longer, otherwise the room cools down too much |
| Dry laundry outside as much as possible | Prevents moisture from entering the home | Drying indoors is possible, but ventilate extra then |
| Lid on the pan while cooking | Less water vapor is released | Also use the extractor hood if it vents outside |
| Keep ventilation grilles open | Ensures a constant supply of fresh air | Taped-over grilles worsen the problem |
| Wipe away condensation and dry the windows | Prevents water from seeping into the window frames | Do this regularly, not only when there are many drops |
| Reduce the humidity with a dehumidifier | Removes moisture from the air, even if you cannot ventilate | Does not replace ventilation |
Many people make the mistake of only combating moisture with a device. In our article about common mistakes when combating moisture in the home you can read where it often goes wrong.
When does a dehumidifier help against condensation?
A dehumidifier can be useful if you continue to retain a lot of moisture despite good ventilation, for example due to drying laundry indoors, a poorly ventilated room or a damp period. It removes water vapor from the air and collects it in a tank, so that less moisture can condense on the glass. Milieu Centraal does indicate that dehumidifiers and moisture absorbers mainly tackle temporary problems and are not a replacement for ventilation. So see a dehumidifier as a supplement, not a replacement.
How much moisture you see also depends on the window itself. Single glazing is colder than double or high-performance glass and therefore fogs up faster. A dehumidifier does not solve a cold window, but it does lower the moisture content, which results in less condensation.
The Dynter DH251 dehumidifier
The DH251 is a compact dehumidifier for living spaces up to 55 m², light enough to move to the room where the moisture accumulates.
Product name: Dynter AirPure DH251 dehumidifier
Dehumidification: up to 900 ml per day, suitable for spaces up to 55 m²
Water tank: 3800 ml, with a safety sensor that switches off the device when the tank is full
Consumption and size: 80W, 24 x 13.4 x 37 cm, 2.51 kg
Extra functions: night mode (display off), timer function from 1 to 24 hours and ambient light
How often you need to empty the tank can be read in our article how often do you need to empty the water tank of a dehumidifier.
Frequently asked questions
Why are my windows only fogged up in the morning?
At night, the glass cools down while moisture is released in the bedroom due to breathing. Without air exchange, that moisture condenses on the cold windows.
Should I always wipe away condensation on windows?
Yes, it is wise to remove the water so that it does not seep into the window frames. In addition, tackle the cause by ventilating and limiting moisture.
Does heating the room help against condensation?
A slightly warmer window condenses less, but heating alone without ventilating keeps the moisture in the home. Therefore, combine heating with ventilation.
Can a dehumidifier completely prevent condensation?
That cannot be guaranteed. It lowers the humidity, which results in less condensation, but on very cold windows, some condensation can still occur.
When should I call in a professional?
Do you see mold, damp spots in walls or does it continue to return despite measures? Then have an installer or building advisor investigate the cause, for example a leak or inadequate ventilation.
Less moisture in the home with Dynter
Do you want to get the humidity in the home under control? View the Dynter DH251 dehumidifier or our entire range in the collection dehumidifiers.