Dealing with damp and condensation

We at National Energy Action have produced a series of advice leaflets to help you with your energy bills, including this one on damp and condensation.

During the colder months damp and condensation become a major problem in many British homes.

Condensation is caused when warm, moist air hits a cold surface such as a window or external wall and condenses, running down the cold surface as water droplets. If left this can develop into black mould which looks and smells bad and can cause health problems as well as thousands of pounds worth of damage to clothes, furniture, books, shoes and decorations.

Condensation can be a problem in any property no matter its age. It is often worse in homes that have been modernised as ventilation and the circulation of air is reduced. Controlling ventilation and air circulation around the home is very important in the prevention of condensation because this allows moisture-filled air to escape to the outside, preventing future problems inside your home. Rising or penetrating damp can cause problems in your home although it is less common than condensation.

Rising damp

Rising damp is caused by a failed or ‘bridged’ dampproof course. This allows moisture in the ground to rise up through the ground floor walls of your home, sometimes to a height of one metre. You can usually identify rising damp because it is often associated with a tide mark at the edge of the area of damp caused by salt deposits.

Penetrating damp

Penetrating damp is classed as any water that finds its way inside from the outside. It can occur
at all levels of the building and is usually higher up. Overflowing gutters, missing roof tiles, leaking pipes and downspouts, badly fitting windows/ doors and damaged pointing, cladding or flashing or render as well as covered air bricks can all be a source of penetrating damp.

Typical signs of penetrating damp are:

  • growing areas of damp on walls or ceilings
  • blotchy patches on walls
  • wet and crumbly plaster
  • signs of spores or mildew
  • drips and puddles


Condensation can cause mould to form in your home, lead to staining/ damaging wallpaper, wall surfaces, window frames, furniture and clothing. The mould and its spores carry the musty smell that is often associated with a damp house. Black mould can’t grow where salt deposits are present (as with rising damp) and is therefore a sign of condensation

Water vapour is generated in your home in many ways but the main causes are:

  • steam from cooking and boiling the kettle
  • baths and showers
  • drying clothes inside
  • unsuitable venting of tumble dryers

The best way to deal with mould is to remove it from walls using a special fungicidal wash which should be used in line with the manufacturer’s instructions. Special paints are also available that will delay the return of the mould, but unless you take steps to reduce condensation it will eventually grow back.

Areas prone to condensation

The following areas are particularly prone to condensation:

  • cold surfaces such as mirrors, windows and window frames
  • kitchens and bathrooms where a lot of steam is created
  • external walls, walls of unheated rooms
    and cold corners of rooms
  • wardrobes/cupboards and behind furniture against an external wall and a lack of ventilation

Reducing condensation

There are four things to consider when dealing with a condensation problem – heating, insulation, ventilation and excess moisture.


Condensation is most likely to be a problem in homes that are underheated.

Try to keep temperatures in all rooms to above 15°C as this will reduce condensation forming on external walls.


Insulating your home will have a threefold value in tackling the problem:

  • warming the surface temperature of walls, ceilings and windows
  • generally increasing the temperature of the home
  • reducing heating costs thus allowing the home to be heated to a higher standard more affordably.


Condensation will occur less if you allow air to circulate freely. Make sure vents and airbricks are not covered or obstructed.

Reduce the moisture

Condensation in the home occurs when there is too much moisture in the air. Take steps to reduce the amount of moisture in the air by following some of our top tips.

Did you know?

  • A family of four can add moisture to the air equivalent to 30 to 40 litres of water a week just by breathing
  • Showering, cooking, bathing and washing can add 15 to 20 litres a week
  • Drying clothes indoors can add 10 to 15 litres a week

Top tips to reduce condensation

  1. In cold weather try and keep temperatures between 18-21°C in main living areas whilst indoors.
  2. Don’t block airbricks or air vents.
  3. To kill and remove mould wipe down wall and window frames with a fungicidal wash
    which carries a Health & Safety Executive approved number.
  4. Dry washing outside whenever possible.
  5. Don’t dry clothes on radiators. This will make your boiler work harder to heat your house and cost almost as much as using a tumble dryer, whilst creating a lot of condensation.
  6. If you have to dry clothing indoors and don’t have a tumble dryer, place clothes on a drying rack in a room where a window can be opened slightly and keep the door closed.
  7. No drying rack? Put your clothes on hangers and hang from a curtain pole above a slightly opened window.

Other top tips to reduce condensation in your home

In the living room

  • Open window trickle vents during the day or when going out, or open windows for at least 10 minutes every day
  • Lay thick carpet with a good thermal underlay
  • Hang thick, heavy lined curtains during the winter to help keep the room warm

In the kitchen

  • Close internal doors whilst
    cooking and open a window
  • Use an extractor fan if you have one
  • Put lids on pans (this also reduces boiling times and helps save money)
  • Only boil as much water as you need in a kettle to reduce steam and save money

In the bedroom

Wipe down windows with a window squeegee

  • Open window trickle vents during the day or when going out, or open windows for at least 10 minutes every day
  • Don’t put furniture, including beds,
    against any external walls and try to leave a gap between the wall and furniture to allow airflow
  • Lay thick carpet with a good thermal
  • Hang thick, heavy lined curtains during the winter

In the bathroom

  • Open windows whilst bathing/washing and leave them open for about 20 minutes after, if it is safe to do so
  • Use an extractor fan if you have one
  • Take shorter and cooler showers
  • When running a bath put the cold water in first; this results in significantly less condensation
  • Wipe down windows/mirrors/tiles/shower doors with a window squeegee and mop
    up the moisture with an absorbent cloth which can be wrung out in the sink
  • Don’t leave wet towels lying around.


  • When wallpapering use a paste
    containing a fungicide to prevent
    further mould growth
  • Use thermal lining paper under wallpaper when decorating
  • Use mould-resistant paint on areas prone to mould such as ceilings above windows.

National Energy Action’s Advice Service is a free
support service providing advice to householders in England and Wales on their energy bills and keeping warm and safe in their home. We can also help with benefits advice and income maximisation.

For energy advice call: 0800 304 7159
For benefits advice call: 0800 138 8218