How to stop condensation on windows: a simple daily routine

If you wake up to windows streaming with water, you are not alone. Condensation is one of the most common winter problems in UK homes, and left alone it soaks into sills and seals and gives mould exactly what it needs.

Why it happens

Warm air holds more water than cold air. Everyday life adds moisture to the air in your home: breathing while you sleep, showers, cooking, boiling the kettle and drying clothes indoors. When that warm, damp air touches a cold surface, like window glass, it cools and drops the water it was carrying. That is the condensation you see in the morning.

The five-minute morning routine

1. Clear the glass first thing. Remove the water before it runs onto the sill. A window vac collects it in a tank in seconds; an absorbent microfibre cloth works too. Wring cloths out in the sink rather than drying them on a radiator.
2. Air the room for a while. Open the window for a short spell, or open the trickle vents at the top of the frame and leave them open. Swapping damp air for drier outside air is the single most effective habit.
3. Check the sill and seals. Wipe any pooled water. Black spots on silicone seals are an early sign of mould.
4. Keep doors closed while you cook or shower, and run the extractor fan, so the moisture leaves the house instead of spreading to colder rooms.
5. Check the humidity. A simple hygrometer tells you whether a room is drying out or staying damp. Around 40 to 60% relative humidity is widely recommended for homes.

Habits that make the biggest difference

• Dry washing outside when you can. If you can't, dry it in one room with the door shut and a window open or a dehumidifier running.
• Put lids on pans and use the extractor fan when cooking.
• Keep a small gap between furniture and outside walls so air can circulate.
• Keep the heating steady and low rather than letting rooms get very cold and then very hot. Cold surfaces attract condensation.
• Don't block air bricks, vents or trickle vents.

When to put something in the room

Some rooms stay damp even with good habits: bedrooms with the door shut overnight, box rooms, and rooms with single glazing. Moisture absorbers work without electricity and quietly pull water from the air. For small rooms where they can't keep up, a compact electric dehumidifier helps. Window film can warm up cold single glazing so less water forms on it in the first place.

When it might be more than condensation

Condensation tends to appear on windows and cold corners and gets worse in winter. Damp patches low on walls, tide marks or damp that appears after rain can point to rising or penetrating damp, which needs a surveyor or builder. Our guide Condensation or damp? How to tell the difference explains the signs.

If you rent and mould keeps coming back, tell your landlord in writing and keep a record.