Condensation

by The Gateshead Housing Company & filed under Help in your home - repairs to your home, Improving homes, Improving homes - investing in your home.

What is condensation?

Air can only hold a certain amount of water vapour. The warmer it is the more it can hold. If it is cooled by contact with a cold surface, such as a mirror, a window or even wall, the water vapour will turn into droplets of water condensation.

Condensation can lead to damp and/or patches of mould on walls, furnishings or clothes.

The warmer you keep your home the less likely condensation will occur. In Britain, condensation in houses is mainly a winter problem, particularly where warm moist air is generated in living areas and then penetrates to the colder parts of the building.

The moisture in the air comes from a number of sources within the house. Water vapour is produced in relatively large quantities from normal day-to-day activities.

A five-person household puts about 10kg of water into the air every day, without taking into account any heating.

For example:

  • Breathing (asleep) 0.3kg
  • Breathing (awake) 0.85kg
  • Cooking 3kg
  • Personal washing 1.0kg
  • Washing and drying clothes 5.5kg.

Moisture can also be drawn from the structure of the building into the internal air from below the floor or through the walls and ceilings.

Every home gets condensation at some time – usually when lots of moisture and steam are being produced, eg at bathtimes, when a main meal is being cooked or when clothes are being washed. It is quite normal to find your bedroom windows misted up in the morning after a cold night. There is nothing much you can do to stop this.

But, if your home never seems to be free from condensation, read on.

It is not always easy to tell. But other kinds of damp such as rain or plumbing leaks usually leave a ‘tide mark’.

Condensation is usually found on north facing walls and in corners, in cupboards and under work surfaces – wherever there is little air movement.

If you are not sure what is causing the damp in your home, start by checking pipes and overflows and under sinks to see if there are any obvious leaks.

Have a look outside too. You may be able to see if there are slates missing from the roof or cracked gutters or rainwater pipes.

If you live in a new or recently modernised house or flat, do not forget that it may not have dried out from the water remaining after building work. It usually takes nine to 18 months for this to happen, and you may need to use more heat during that time.

The way you use your home affects how much condensation you get. This does not mean that you should alter your habits drastically – just bear in mind the following tips:

Heating – you will get less condensation if you keep your home warm most of the time.

Insulation will help you do this. But with fuel the price it is, try to remember that:

  • It is important your heating system is checked annually, so that it works efficiently
  • Try to leave some background heat on through the day in cold weather.

Most homes take quite a long time to warm up, and it may cost you more if you try to heat it up quickly in the evening. To keep energy costs down, ask your fuel supplier about their budget schemes. For example, fuel saving stamps, which help to spread the cost of fuel.

Ventilation – the more moisture produced in your home, the greater the chances of condensation, unless there is adequate ventilation. Nobody likes draughts, but some ventilation is essential.

Windows – in winter, open windows a little, but only for as long as they are misted up. If you fit draught stripping, leave a space for a small amount of air to get through.

Chimneys – never block these up completely. If you’re blocking up a fireplace, fit an air vent to allow ventilation.

Drying clothes – drying clothes indoors, particularly on radiators, increases condensation, unless you open a window to allow air to circulate. If you have a tumble dryer that is not vented to the outside, you will need to allow more ventilation when you use it.

Doors – keep kitchen and bathroom doors shut when cooking, washing or bathing. Otherwise water vapour will spread through the house and condensation could reach other rooms.

Extractor fans – if you have an extractor fan use it when the windows get steamed up while cooking and when taking a bath.

Kettles and pans – don’t allow kettles and pans to boil for any longer than is needed.

Cupboards and wardrobes – do not overfill cupboards and wardrobes. Always make sure that some air can circulate freely by fitting ventilators in doors and leaving a space at the back of the shelves.

Top tips to reduce your condensation

  • Make less moisture
  • Improve ventilation
  • Heat the house properly
  • Do not use portable Liquid Petroleum Gas (LPG) or paraffin heaters
  • Keep kitchen and bathroom doors shut when in use
  • Use pan lids when cooking
  • Dry clothes outside.

Report damp and mould using our online form.

Dampness and mould guide (PDF)