Reduce condensation in your home

What is condensation and what causes it?

Condensation occurs when warm air comes into contact with cold surfaces. Warm air can hold more moisture than cold air, which is why you sometimes get moisture on cold surfaces. We generate moisture in our homes through normal living for example when we bathe, shower, boil kettles and even breathe. When there is a lot of moisture and we don't let it out, it has to find somewhere to settle. When the damp air hits cool surfaces, such as walls and ceilings, and windows the water vapour in it condenses back into water droplets. This condensation can cause mould to grow on these surfaces.


What is Mould?

Mould is fungi that can grow on almost any damp surface. You may notice a damp or musty smell before you see any visible signs of damp, because condensation often forms behind cupboards and wardrobes, where the air doesn’t circulate. Although mould is often black and speckled, it can also be green, yellow or brown in colour.


Ventilate to remove moisture in the home

The presence of condensation and mould does not mean that there is anything wrong with the building. You can help to minimise condensation by increasing the airflow. You may have noticed fixed air vents around your home. Please clean them regularly so they do not block up.


Keep your home warm

Heat your home at low levels for a long time rather than high levels for a short time. This will help get rid of any cold surfaces in your home and reduce condensation. Only use a dry heat source, for example, gas central heating. Dry-washing outside the property whenever you can, keep the doors closed and the windows open. Permanently vent your tumble dryer outside. When a room is in use keep a small window and trickle vents open. Close kitchen and bathroom doors when cooking or bathing. Make sure other doors are closed, especially bedroom doors as bedrooms are normally slightly colder and will attract moisture. Treat and remove the mould using fungicidal products and a soft cloth from a DIY store.


What can you do to reduce it?

1. Try to produce less moisture

  • Try to dry your washing outside whenever you can. You can hang drying items in the bathroom, keeping the door closed and the window wide open.
  • Permanently vent your tumble drier to the outside of your home, using a suitable kit recommended by the manufacturer of the appliance.
  • While cooking, always cover pans and don't leave kettles boiling.

2. Ventilate well to remove moisture

  • When a room is in use, keep a small window and/or a trickle vent open
  • Ventilate bathrooms and kitchens by opening the window even for short periods of time after use.
  • Close kitchen and bathroom doors when cooking or bathing.
  • Make sure other doors are closed, especially bedroom doors as bedrooms are normally slightly colder and will attract moisture

3. Insulate and heat your home

  • Keep your home warm with insulation, draught-proofing and heating: this reduces the risk of condensation.
  • A constant, low-level form of heating provides the most economical form of heat and reduces the likelihood of condensation.

4. How to treat mould yourself

  • Treat and remove the mould using a fungicidal product available in DIY stores.
  • Wipe down windows, frames and other affected areas with the fungicidal wash taking care to follow the manufacturer’s recommendations.


If you’ve followed our advice and made some changes to things you do in your home and are still having problems with condensation, damp or mould, please call our Customer Services 020 8709 4300


Download our leaflet on Condensation and Mould

Condensation and mould