What is condensation?

Condensation occurs when warm moist air comes into contact with a cool surface and water droplets form. You notice it when you see your breath on a cold day, or when your bathroom mirror steams up. Condensation typically appears on cold surfaces particularly on outside walls where there is not much air movement or to the sides of windows. It often appears as black mould growth in corners near the skirting and on the ceiling.

Areas with poor ventilation are also prone to condensation. This includes surfaces behind furniture such as beds or in or behind wardrobes and cupboards, especially where they are placed against an outside wall. Condensation can happen in any room but is most likely to occur in your bedrooms and hallway as they are cooler. If left unchecked it can lead to damp and mould growth occurring which is often the first sign of a serious condensation problem.

Tackling condensation in your home

When the weather gets colder condensation in the home can increase which can cause damp and mould. There are simple measures you can take and the following information and advice from Harlow Council will help you tackle condensation in your home.

Produce less moisture in your home

  • Try not to dry washing on radiators. Dry outside or in the bathroom with the window open.
  • Cover saucepans when cooking.
  • When filling the bath, try running the cold water first, then add the hot – it will reduce the steam, which leads to condensation, by 90 per cent.
  • Keep the bathroom and kitchen doors closed during bathing, cooking or washing to prevent moisture escaping to the rest of your home.

Ventilation to remove moisture

  • Allow excess moisture to escape from the air by ensuring trickle vents are left open and windows left ajar when your home is occupied.
  • Make sure you are using extractor fans in your bathroom and kitchen if installed. Keep the fans on for at least 20 minutes after bathing and cooking.
  • If you use a tumble dryer ensure that it is vented to the outside of your home. Simple kits can be purchased from DIY shops.

Remove condensation from cold surfaces

  • Try to maintain a low level of heating throughout the day even if your home is unoccupied.
  • Try to ensure that the heat throughout your home is even by leaving doors to unheated rooms open.
  • Portable bottled gas heaters produce a lot of moisture. Try to avoid using these to heat your home as they may encourage condensation.

Heating your home

  • Mould will form where condensation is allowed to sit. Wipe down all condensation on glass or window sills with a clean cloth as soon as it appears.
  • If mould appears ensure it is removed as early as possible with a fungicidal wash that carries a Health and Safety Executive (HSE) “approved number”
  • Always ensure that you follow the manufacturer’s instructions for its safe use.


Mould is a living organism and needs to be killed.

Dry clean mildewed clothes and shampoo carpets. Do not brush or vacuum mould as this can increase the risk of respiratory problems.

Wipe down affected surfaces with a Health and Safety Executive approved fungicidal wash and follow the manufacturer’s instructions. This should be continued as a regular cleaning routine. If the walls are to be decorated, use a good quality anti-mould paint to help prevent mould reoccurring. Avoid the use of wallpaper where rooms are susceptible to condensation and mould.

The only lasting way of avoiding severe mould is to eliminate condensation and dampness.