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Internal condensation


The air surrounding us in our home always contains water vapour which is not visible.

Condensation is caused when the air becomes saturated with excess water vapour produced by normal living activities such as cooking, washing up, bathing, laundry and heaters.

In the past, excess water vapour could escape up a chimney, through a door jamb or window joints and other outlets.

However modern home comforts including central heating, double glazing and insulation have created rooms that are warmer but often have less ventilation meaning the excess water vapour has nowhere to go.

When the vapour that is trapped inside comes into contact with a surface that is at a lower temperature than itself, the air is chilled and the excess water vapour eventually forms as droplets of moisture on that surface, which is commonly on the glass of a window or door.

While condensation cannot be eliminated it can be managed by following these guidelines:

  • In cold weather, turn on some form of heating more frequently.
  • Ensure that wall vents and windows are open and kept clear.
  • When cooking or bathing ensure bathroom and kitchen internal doors are closed and windows kept open. Consider the installation of an extractor fan or cooker hood. 
  • Allow the room’s warmth to reach the windows and use a fixing which holds curtains at least 15-20cm away from the glass to allow free movement of warm air.
  • Provide natural ventilation by opening a window for at least a few minutes each day to allow a minimum of one complete air change.