Condensation and moisture problems

What is condensation?

Condensation forms when water vapour contained by the air comes into contact with cold surfaces and condenses to form dampness or water droplets. Air can contain varying amounts of water vapour; warm air can hold more water vapour than cold air. When warm air comes into contact with a colder surface, it cools down and can’t retain the same amount of water vapour. The excess water vapour turns back to a liquid and forms condensation.

Water vapour is invisible in air and is formed when you breathe and when you carry out normal daily activities in the home. It is also formed as the materials used in the construction of new houses dry out.

How to reduce condensation

There are three ways in which you can combat condensation:

  1. Reduce the amount of water vapour released into the house – use lids when cooking, avoid drying clothes indoors, ensure bathroom and kitchen extract fans are working properly.  
  2. Remove water vapour through continuous ventilation – open windows and trickle vents, install a positive pressure loft unit, humidity controlled dMEV fans or a whole house ventilation system
  3. Increase temperature of cold surfaces – install double glazing, improve wall insulation, avoid leaving heating turned off for long periods during winter

For more information, check out the following links:,31929,en.pdf