Condensation is the most common kind of damp in English homes. The English Housing Survey found serious condensation in 3% of homes in 2024, more than penetrating damp (2%) or rising damp (1%). It is usually at its worst in winter.

Why winter makes it worse

Everyday life puts a lot of water into the air: cooking, showers and baths, washing up, drying clothes and even breathing. When that warm, moist air meets a cold surface, the water condenses. In winter:

  • walls, window frames and glass are colder, so more surfaces are cold enough for water to settle
  • windows stay shut to keep the heat in, so moist air has nowhere to go
  • more washing gets dried indoors
  • rooms that are heated only now and then cool down quickly, and their walls stay cold

Mould can then grow where the surface stays damp.

Where to look

  • window frames, sills and the reveals around windows
  • corners of rooms and the top of outside walls
  • behind wardrobes, beds and sofas pushed against outside walls
  • bathrooms and kitchens
  • cupboards on outside walls

What helps

The government's guidance on damp and mould suggests some small, reasonable changes. They help, but they are not a substitute for fixing a building problem.

  • Put lids on pans when cooking.
  • Keep internal doors shut while cooking or bathing, so the moisture doesn't spread.
  • Use the extractor fan in the kitchen and bathroom, and leave it running for a while afterwards.
  • Leave windows on the "vent" setting (open slightly but locked) or keep trickle vents open.
  • Dry washing outdoors when you can. If you can't, dry it in a room with the door shut and a window open.
  • Leave a small gap between furniture and outside walls.
  • Wipe condensation off windows and sills in the morning.
  • Keep rooms reasonably warm if you can.

Cleaning small patches

Small areas of mould can usually be cleaned safely yourself with a mould and mildew product, wearing a mask, gloves and goggles. See cleaning small areas yourself. Larger areas need professional removal.

If it keeps coming back

Mould that returns quickly after cleaning usually points to something more than day-to-day moisture: an extractor fan that doesn't work or isn't powerful enough, a cold spot such as a poorly insulated wall or ceiling, a hidden leak, or water getting in from outside. That is when a survey is worth it. See mould testing and damp surveys.

If you rent

Report condensation mould to your landlord in writing. The government's guidance is clear that it is "totally unreasonable" to blame damp and mould on "lifestyle choices", because cooking, bathing and drying laundry can't be avoided. Fixing inadequate ventilation or insulation is the landlord's job. See who has to fix damp and mould in a rented home.

Sources

Tags

winter mouldcondensationpreventionheatingventilation