Condensation happens when moisture in warm air comes into contact with a cold surface and turns into water droplets.

This happens more in rooms where there is a lot of moisture, such as bathrooms and kitchens, or in rooms where there are a lot of people.

Condensation also forms in cold rooms when there is little movement of air.

Condensation can form behind furniture, in corners of rooms or in wardrobes.

Condensation can be caused by:

• Too much moisture in the air, often created by steam from cooking and washing.

• Using portable paraffin and bottled-gas heaters. (Each litre of paraffin burned releases one litre – three pints – of water vapour into the atmosphere.)

• There not being enough ventilation in your home.

• Extreme temperatures (for example, a kitchen being very warm and a bedroom very cold).

• Drying clothes inside the home, especially over radiators.

• Moisture produced by everyday activities.

Condensation can cause mould to form on walls, furniture and soft furnishings (for example, curtains).

Damp conditions can damage plasterwork and rot wooden window frames. It can also increase the number of house mites.

If anyone in your home has a breathing condition such as asthma or bronchitis, it is important that you control condensation because mould and house mites may make these conditions worse.

Our everyday activities add extra moisture to air inside our homes.

Even breathing adds some moisture (remember when you breathe on cold windows and mirrors it mists them up).

One sleeping person adds half a pint of water to the air overnight, and at twice that rate when active during the day.

To give you some idea of how much moisture could be produced in a day, here are a few examples:

• Two people active for one day = 3 pints

• Cooking and boiling a kettle = 6 pints

• Having a bath or shower = 2 pints

• Washing clothes = 1 pint

• Drying clothes = 9 pints

• Using paraffin or bottled-gas heater = 3 pints

• Total amount of moisture produced in your home in one day = 24 pints

Here are some simple steps you can take to reduce condensation in your home:

• Dry your windows and window sills every morning.

• In the kitchen and bathroom, dry any surfaces that get wet.

• Wring out your used cloth rather than drying it on a radiator or in front of a heater.

• Use a fungicidal cleaner to clean any walls, ceilings and paintwork affected by mould. Use a mould and mildew remover that carries a Health & Safety Executive (HSE) approved number, and make sure you follow the instructions.

• If you use a tumble dryer, make sure it is vented to the outside (unless it’s a condensing dryer).

• 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.

• When filling your bath, run the cold water first then add the hot. (This will reduce the amount of steam by 90%.)

• Don’t use your gas cooker to heat your kitchen. (Burning gas produces moisture. If your windows mist up, this is a sign of moisture.)

• Avoid drying your clothes on radiators or in front of a fire. Hang your washing outside or in the bathroom with the door closed and window slightly open. Always make sure you put the extractor fan on if you have one.

Ventilation can help reduce condensation in your home by allowing moist air to escape and drier air from outside to come in.

Here are some ways you can increase the ventilation in your home:

• For about 30 minutes a day, leave a small window downstairs and a small one upstairs slightly open. The windows should be on opposite sides of the home, or diagonally opposite if you live in a flat. At the same time, open all the inside doors. This will allow drier air to circulate throughout your home. This is called ‘cross ventilation’.

• When cooking, washing up or washing by hand, open a window slightly (this is as good as opening it fully). Switch on your extractor hood or extractor fan if you have one.

• When using your kitchen and bathroom, close the door to prevent moisture escaping to the rest of the home and open a small window afterwards for about 20 minutes.

• Use an extractor fan if you have one. They are cheap to run and are effective in quickly removing moisture from a room.

• Leave your bedroom window slightly open at night, or use trickle ventilators if you have them.

• Keep a small gap between large pieces of furniture and the walls. And if possible, place wardrobes and other furniture against internal walls rather than external walls. Never overfill wardrobes and cupboards as this restricts the flow of air.

Warm air holds more moisture than cooler air. So cool air is more likely to leave droplets of condensation round your home.

Air is like a sponge, the warmer it is, the more moisture it will hold. Heating one room to a high temperature and leaving other rooms cold makes condensation worse in the rooms that aren’t heated.

It is better to have a constant level of heat throughout your home, ideally between 17°C and 21°C.

Keeping the temperature constant will help control condensation and works out cheaper than constantly heating a cold home to the temperature you want.

It is important that you make the following changes to control condensation in your home:

• Produce less moisture.

• Put lids on pans while cooking.

• Don’t dry clothes in front of a fire or over radiators, dry them outside where possible or use the bathroom with the door shut and the room well ventilated.

• Vent your tumble dryer to the outside.

• When running a bath, put cold water in first as this reduces the amount of steam.

It is important that you reduce the amount of moisture in your home by:

• Improving ventilation by opening windows, using trickle vents and by using fans where provided.

• Maintaining a constant temperature of between 17°C and 21°C.