Reduce Condensation on Windows
Stop condensation forming on your windows by cutting indoor humidity, improving ventilation, and wiping away moisture before it causes mould or rot.
Quick answer
Run a dehumidifier or moisture absorber, keep extractor fans on during cooking and bathing, and wipe wet windows with a microfibre cloth each morning. Fit trickle vents if your windows allow them.
Condensation on windows happens when warm, moist indoor air hits cold glass. Left unchecked, it can lead to black mould and damaged window frames. You can cut condensation quickly with a few changes to how you heat, ventilate, and dry the air in your home.
What you’ll need
- moisture absorber tubs or electric dehumidifier
- extractor fan in kitchen and bathroom
- microfibre cloth
- window vacuum (optional)
- trickle vent inserts (if compatible with your windows)
- laundry airer or outdoor line
Step by step
- 1
Wipe windows every morning
Run a microfibre cloth or window vacuum along the glass and frame to remove standing water. Do this before the moisture evaporates back into the room. Wash the cloth regularly.
- 2
Use a dehumidifier or moisture absorber
Place an electric dehumidifier in the worst-affected room and empty the tank daily. In cupboards or smaller spaces, use refillable moisture absorber tubs. Keep the humidity level between 40 and 60 percent if your device has a gauge.
- 3
Turn on extractor fans and keep them on
Run the kitchen extractor fan while you cook and the bathroom fan during baths and showers. Leave each fan running for 15 to 20 minutes afterwards to clear lingering steam.
- 4
Improve airflow around the home
Open windows slightly for 10 to 15 minutes each day, even in winter. Leave doors ajar between rooms so air can circulate. Move furniture a few centimetres away from external walls to prevent cold spots.
- 5
Dry laundry wisely
Dry clothes outdoors when possible. If you must dry indoors, use a heated airer in a well-ventilated room with the door closed and a window slightly open. Do not drape wet washing directly on radiators without ventilation.
- 6
Consider fitting trickle vents
If your windows are compatible, fit trickle vents to the top of the frames. These small vents let a constant flow of fresh air in without opening the window fully. Follow the manufacturer's fitting guide or hire a professional.
Persistent condensation can lead to black mould, which may damage your health and your home. If you notice mould on window frames, walls, or sills, clean it promptly with an appropriate mould remover. Wear rubber gloves and keep the room ventilated while you work. Do not ignore musty smells or peeling paint near windows.
Common mistakes
- Keeping windows sealed tight all winter with no ventilation.
- Drying large loads of laundry indoors without opening a window or running a dehumidifier.
- Turning off the extractor fan as soon as cooking or bathing finishes.
- Ignoring condensation on wooden window frames, which can rot over time.
Frequently asked
Will double glazing stop condensation completely?
Double glazing reduces condensation on the glass itself because the inner pane stays warmer. However, it will not stop condensation if humidity inside the home is very high. You still need ventilation and moisture control.
Is condensation the same as a window leak?
No. Condensation forms as water droplets on the inside surface of the glass. A leak usually shows as water entering around the frame or between the panes of sealed double glazing.
Can condensation damage my window frames?
Yes. Constant moisture can rot wooden frames, corrode metal fittings, and cause mould on any material. Wiping windows dry each morning and controlling humidity will protect them.
Do I need an expensive dehumidifier?
Not necessarily. Small moisture absorber tubs work well in cupboards and bedrooms. A basic electric dehumidifier is useful for larger rooms or persistent problems. Match the size of the unit to the room.
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