Condensation ? how to avoid it !

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Condensation ? how to avoid it !

Condensation (and mould) can cause much frustration, expense and cleaning during the winter months. To try & help, we have pulled together a list of what can cause condensation and some suggestions to help avoid the resulting mould.

What is Condensation? The Science. . .

All air contains water. Warm air holds more moisture than cold air. So when warm, moist air comes into contact with either colder air or a colder surface, the water is released and forms condensation. Condensation is most obvious on hard surfaces (i.e. windows or tiles) but it can actually form on any surface. Areas with poor ventilation like behind furniture and in cupboards often highlight a condensation problem with the appearance of mould.

Conditions for Condensation

A 5 person household produces over 10 litres of water into the air every day (excluding any from heating) Main contributors are:

  • breathing 1.2 L
  • cooking 3 L
  • personal washing 1.0 L
  • washing and drying clothes 5.5 L

Modern life also means many houses remain unoccupied and unheated for large parts of the day. The moisture-producing activities are then concentrated into relatively short periods of time in the mornings and evenings, exacerbating any condensation issues.

How do you control Condensation?

Essential there are 3 basic options for reducing condensation in a property.

Minimise the impact of moisture -producing activities:

  • Turn down the thermostat for central heating – it will help save you money too
  • Keep lids on pots and pans, open the kitchen window but close the door to stop it spreading throughout the rest of the property
  • Tumble dryers should be ducted directly to the outside of the house
  • Ideally try to dry clothes outdoors or in a cool area of the house – it may sound strange, it will take longer but less moisture will be held in the air at any one time.
  • When people come in with wet coats, hang them outside to dry. A good reason for a porch.

Increase the ventilation:

  • After a bath or shower, try to ventilate the room to the outside, not to the rest of the house – just opening a window slightly (and closing the door) will help.
  • When drying clothes indoors, ventilate the room.
  • Try to increase ventilation. Add forced ventilation/extraction to areas which produce a lot of moisture (kitchen, bathroom).
  • Don’t fill cupboards up completely, especially if they have clothes in them. Leave space for the air to circulate

Trap the moisture:

  • Moisture traps are a cheap and really effective way of controlling condensation. Kilrock moisture traps (available at Wilkinsons) work particularly well. They require no batteries or electricity and start working immediately by turning moisture in the air into either water or as a gel within a container, which can then be emptied.
  • Dehumidifiers can draw out   surprisingly large amounts of water and are readily available from most high   street shops. They will need emptying periodically but the cost is  surprisingly reasonable at about 2p – 3p / hour. Standard dehumidifiers work  best in well heated rooms with high humidity, however in “cold” rooms such as  a garages, conservatory’s or workshops you need a machine with a function  called hot gas defrost.

Mould growing on a wall

If mould does appear, there are a number of widely available sprays available (Dettol Anti Mould) that will kill it and prevent it (temporarily) from returning. White vinegar sprayed onto the surface does the same job. Wash-able  items can be put through a cycle to kill / remove the mould (the hotter the better) but it is of course vital to ensure that they are thoroughly dried to avoid the problem repeating itself.


Mould and condensation can be controlled. Being aware of what causes it and what to do to avoid it goes a long way to minimise your chance of having to deal with it.