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Luton Borough Council

Condensation, damp and mould


Here you can find tips to prevent condensation and mould in your home and how to treat it if you already have it. Plus, how to tell if it’s condensation or damp.

What is condensation?

There is always some moisture in the air, even if you cannot see it.  If air gets cold it cannot hold all the moisture produced by everyday activities and some of this moisture appears as tiny droplets of water, most noticeable on windows on a cold morning. This is condensation. It can also be seen on mirrors when you have a bath or shower, and on cold surfaces such as tiles or cold walls.
Condensation forms on cold surfaces and places where there is little movement of air. In your home it can appear on, or near:

  • windows
  • in corners
  • behind wardrobes and cupboards

Condensation or damp?

Condensation occurs in cold weather, even when the weather is dry. It does not leave a ‘tidemark’ round its edges on walls.  If there is a ‘tidemark’ this dampness might have another cause, such as water leaking into your home from a plumbing fault, loose roof tiles or rising damp.

Problems which can be caused by excessive condensation

Dampness caused by excessive condensation can lead to mould growth on walls and furniture, mildew on clothes and other fabrics, and the rotting of wooden window frames. Also, damp humid conditions provide an environment in which house dust mites can easily multiply. The presence of mould and dust mites can make existing respiratory conditions such as asthma and bronchitis worse.

First steps against condensation

You will need to take proper steps to deal with condensation, but meanwhile there are some simple things you should do straight away.

Dry your windows and window sills every morning, as well as surfaces in the kitchen or bathroom that have become wet. Wring out the cloth rather than drying it on a radiator

First steps against mould growth

First treat the mould already in your home, then deal with the basic problem of condensation to stop mould reappearing.
To kill and remove mould, wipe down or spray the walls and window frames with a fungicidal wash that carries a Health and Safety Executive (HSE) ‘approval number and ensure that you follow the instructions for its safe use. These fungicidal washes are often available at local supermarkets and are often called mould and mildew removers. Dry-clean mildewed clothes and shampoo carpets. Do not try to remove mould by using a brush or vacuum cleaner.
But remember: the only lasting cure for severe mould is to get rid of the dampness.

What causes condensation?

There are four main factors that cause condensation:
  • too much moisture being produced in your home
  • not enough ventilation
  • cold surfaces
  • the temperature of your home

Reduce the potential for condensation by producing less moisture

  • hang your washing outside to dry if at all possible, or hang it in the bathroom with the door closed and a window slightly open or extractor fan on. Don't be tempted to put it on radiators or in front of a radiant heater
  • if you use a tumble drier make sure it is vented to the outside or that it is of the new condensing type
  • always cook with pan lids on and turn the heat down once the water has boiled. Only use the minimum amount of water for cooking vegetables
    ventilate your kitchen when cooking or washing up. Open a window or use a cooker extractor if you have one
  • keep kitchen and bathroom doors closed to prevent moisture escaping into the rest of the house
  • ventilate you kitchen and bathroom for about 20 minutes after use by opening a small window or using an extractor fan if you have one
  • ventilate your bedroom by leaving a window slightly open at night or using trickle ventilators if fitted (but remember your security)
  • reduce the risk of mildew on clothes by not overloading your wardrobe and leave a small gap between large pieces of furniture and the walls

For further information on damp and mould in rented homes, visit the Shelter Page. You can also download the leaflet below for information on preventing and tackling condensation.


Contact info
Private Sector Housing Enforcement
4th Floor Town Hall Extension, Luton, LU1 2BQ

[email protected]


© 2024 Luton Council, Town Hall, Luton LU1 2BQ