Damp & Condensation

What is condensation?

There is always some moisture in the air, even if you cannot see it. You notice it when you see your breath on a cold day, or when the mirror mists over when you have a shower or bath. Condensation is caused when moisture held in warm air meets a cold surface like a window or wall and condenses into water droplets. If this happens regularly, mould may start to grow. This usually appears on cold outside walls and surfaces, and in places where the air does not circulate well. The moisture created can also damage clothes, furnishings and decoration and leave a musty smell. 

What causes condensation?

Condensation usually occurs in winter because the building is cold and windows are opened less so moist air cannot escape. 

Condensation will form on cold surfaces like windows and walls and even on clothes and in wardrobes. It is important that you remove this condensation because if you leave it, it will cause mould, mildew and rot, especially if rooms are not suitably heated and ventilated. 

The amount of moisture that can be produced in pints in one day by an average family of four:

  • Two people at home for one day = four pints
  • Cooking and boiling kettles = six pints
  • Having a bath or shower = two pints
  • Washing clothes = one pint
  • Drying clothes = one pint 
  • Four people sleeping = three pints
  • The total amount of moisture produced in your home for one day = 17 pints 


How can I prevent it?

  • Control moisture: keep lids on pans, dry clothes outdoors or in a tumble dryer with ventilation, preferably through walls to the outside. 
  • Control where moisture goes: close internal doors, open windows to let moisture escape, wipe away moisture from windows and walls and remember to keep your extractor fans on. These fans are very cheap to run. 
  • Close bedroom doors at night and open a window slightly to allow ventilation (make sure you close the window when you go out) or keep trickle vents open if they are fitted inside your double glazing frames. 
  • Clean mould away effectively: you can buy mould and mildew sprays from most supermarkets to clean and kill the bacteria present in mould growth. 
  • Increase air flow: move furniture, wardrobes and beds away from cold walls and allow air to flow around in these areas. This will help reduce mould.
  •  Keep your home warm whenever possible: Keeping a low background heat (ideally between 18 and 22 degrees centigrade) is often more effective and can cost less than having the heating on full for several short periods during the day.
  • Do not restrict the radiators from radiating its heat out to reach walls that may have cold spots. Radiators are not meant to dry clothes on. They are designed to make your home more comfortable. 
  • Humidity sensitive fans: They help remove moisture from your home and reduce the likelihood of mould growth. They provide constant background ventilation and adjust when they detect high humidity, for example when showering, bathing or cooking. These fans are very cheap to run.
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