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Why Your Windows Are Wet Every Morning, and How to Stop It

Condensation forms when warm, moist air meets a cold surface. To stop it, reduce the moisture you create, remove what remains with ventilation or a dehumidifier, and keep surfaces from getting too cold.

Updated 10 October 2026. Contains paid links. As an Amazon Associate I earn from qualifying purchases.

Where the water comes from

People release moisture overnight simply by breathing. Showers, cooking and drying clothes add several litres more each day. When that air reaches cold glass, the water condenses, and by morning the windows and sills are wet.

Fixes in order of cost

1. Wipe the glass each morning. A squeegee or window vacuum takes a minute and keeps mould off the frames.
2. Open the trickle vents at the top of the window frames and leave them open.
3. Cover pans and use the extractor when cooking. Run the bathroom fan during showers and for about 15 minutes after.
4. Avoid drying clothes in bedrooms. Our guide to drying clothes indoors covers alternatives.
5. Run a dehumidifier in the worst-affected room overnight.
6. Keep a low, steady temperature rather than short bursts of heat, so walls and glass stay warmer.

When it is more than condensation

Damp patches low on walls, tide marks or crumbling plaster point to a leak, rising damp or penetrating damp. Have a professional inspect it. If you rent, report it to your landlord in writing.