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Condensation and ventilation: preventing damp in your home

Posted by Anna Carlini on 20 June 2017 at 4:50 pm

Ventilation is a surprisingly important element in keeping your heating bills down. How? Because a home that can’t “breathe” is one which traps moisture on the inside and causes damp. Even if a home has high levels of insulation, a damp wall can lose up to 40% more heat than a dry wall[1].

It is always a good idea to thoroughly insulate your property, it will provide greater energy efficiency, lower your heating bills and make your home warmer. But if your house doesn’t have adequate ventilation, then insulation can have the adverse effect of trapping moisture, which can settle and cause damp. Damp is problematic for many reasons; it can cause health problems, mould, and rot. It can even make a house feel colder than it did before you insulated it!

There are many causes of damp, but in this case we are interested in damp caused by condensation, which is usually identified by the mist steaming up windows. Mould also appears in areas around condensation problems, which is why it frequently grows in bathrooms, kitchens and bedrooms. These rooms often have a lot of moisture in the air as a result of using the shower, boiling the kettle and breathing all night! Some students may vividly remember the condensation and mould appearing on the windows and walls of their bedrooms at university.

To put this into perspective, four people living in a three bedroom house create 63 litres (112 pints) of moisture a week just from breathing, cooking, showering and boiling the kettle [2]. Ventilation is the key to getting this moisture out of the air and there are many small things you can do in your home to help: 

  • Put a lid on your pans while cooking
  • Open the window and air the room after a shower
  • Wipe the condensation off the window to dry it and stop the moisture going into the walls
  • Do not overfill your wardrobes and cupboards, the trapped air will not be able to circulate, creating the perfect conditions for mould to grow
  • Install an extractor fan
  • Use dehumidifiers, as these may help to trap moisture
  • Try to avoid drying clothes inside. If you have no choice, make sure the windows are open and door shut to improve ventilation
  • Apply anti-mould paint around your windows
  • Get a hygrometer to monitor humidity levels in your home
  • If you have the resources, consider a whole house ventilation system to ensure that damp from condensation does not return

Taking these simple steps will ensure that whatever the age of your home or level of insulation it may have, you will have enough ventilation to avoid condensation which may lead to further damp problems.


1)      GreenSpec

2)      Envirovent

3)      Sust-it

More information about ventilation and draughts on YouGen.

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1 comments - read them below or add one


MikeSanComment left on: 29 June 2017 at 10:57 pm

I have walls covered by wallpapers and special properties and able to breathe, so mould will not appear. But of course keeping the right air circulation is always the key to prevent mould growing.

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