What is condensation?

Condensation is caused when water vapour meets cold surfaces and condenses to form water droplets. Air can contain varying amounts of water vapour; warm air can hold more water vapour than cold air.

Condensation that forms on surfaces and left can lead to damp and mould, which can affect the health of people living in the home.

How can I stop condensation?

There are four ways you can reduce the chance of condensation in your home (more details are below):

  1. Produce less moisture
  2. Stop moisture spreading
  3. Ventilate moisture away
  4. Provide even heating

1. Produce less moisture

  • Put lids on saucepans while cooking to reduce steam.

  • Fill baths up with cold water first then add hot water.
  • Avoid drying laundry on an airer or radiator. If you need to dry clothes indoors, open the window and close the door of the room where the clothes are drying, so that moisture can escape. Drying laundry indoors puts a surprising amount of moisture into the air.
  • If you use a vented tumble drier, ensure the vent leads to an open window or through an outside wall.
  • Check plumbing for leaks. Inspect damp or regular drops in boiler pressure.

2. Stop moisture spreading

  • While cooking, bathing or washing, use an extractor fan and/or open a window, and keep the door closed. Keep the extractor fan on and/or the window open after you have finished (with the door closed) until all signs of steam/condensation has gone.

  • When condensation appears, wipe it away.

3. Ventilate moisture away

  • Leave trickle vents (slotted vents in window frames) open to remove water vapour when rooms are occupied – even in the winter when your heating is on.
  • Put free-standing wardrobes and other furniture against internal walls, leaving a gap so that air can circulate. Try not to overfill cupboards, wardrobes and drawers so that air can circulate around the contents.
  • Use a mechanical dehumidifier of appropriate size for your home if you do not want to open windows.
  • Opening windows on either side of the dwelling will allow for a through flow of drier air.

4. Provide even heating

  • Keep your home warm to avoid cold surfaces (even when you are out) and remember that it can take a long time for a building to warm up.

  • If out during the day, set your timer so that your home is warm when you return. During cold weather it’s better to leave the heating on during the day to keep an even temperature. It can be set a few degrees lower while you’re out and turned up when home.
  • Keep all rooms heated to a low temperature rather than some rooms heated to a high temperature.

How do I treat mould?

Mould can be dangerous. Always use appropriate protective clothing when dealing with damp. Don’t forget to wear an appropriately rated dust mask to prevent inhalation of mould spores. Use goggles and gloves with chemicals harmful to health.


Sterilise the infected area with a suitable fungicidal wash - available from most DIY stores – and follow the manufacturer’s instructions. Keep checking the affected area for at least a week. If the mould reappears, wash it down again as soon as possible with the fungicidal wash to make sure the area is thoroughly sterilised.


If the treatment appears to have been successful, you can carry out any necessary redecoration. If painting, use a good quality fungicidal paint to help prevent mould growth, but remember that this won’t be effective if it’s later covered by ordinary paint or wallpaper. If wallpapering, use a paste containing a fungicide to help prevent further mould growth. Whilst fungicidal paint/paste can make it more difficult for mould to grow, it may not prevent it entirely.

Dry clean

If mould or mildew is growing on clothing or carpets, you should dry clean them. Don’t disturb mould by brushing or vacuum cleaning, as you can increase the risk of respiratory problems.

Other causes of damp

Condensation causes damp, but it can also be caused by what’s known as penetrating damp – which is caused by moisture coming into the house from outside where there are problems in the structure of your home – and rising damp – which is moisture from under the house coming through a defective (or non-existent) damp proof course in the building.

If you don’t think the damp in your home is caused by condensation, contact your landlord (if you are renting or in social housing) or a damp proofing contractor (if you are an owner-occupier).

Finding help

In the first instance, contact your landlord (if you are renting or in social housing) or find someone to carry out a damp assessment.

If you are not satisfied with the response from your landlord, please contact our Private Sector Housing team through MyEHDC.

Citizens Advice can also advise you on support that may be available to help resolve the problem.