What causes condensation?

There is always moisture in the air, even if you cannot see it. The temperature of the air determines how much moisture it can hold. If air gets cold, it cannot hold all of the moisture produced by everyday activity and releases tiny droplets of water.

Condensation is most often seen in bathrooms or kitchens where large amounts of moisture is produced, or on cold surfaces in rooms where moisture can travel.

There are four main factors that cause condensation:

  • Too much moisture in your home.
  • Not enough ventilation.
  • Cold surfaces.
  • The temperature of your home.

You need to look at all of these factors to solve a condensation problem.

Ways to prevent condensation and mould:

In the kitchen

  • Cook with lids on saucepans and turn the heat down once the water has boiled.
  • Slightly open your kitchen window when you are cooking or washing up and if you have one, use your cooker extractor fan.

In the bathroom

  • When filling a bath, run the cold water first then add the hot – it will reduce steam by 90%.
  • When creating steam open windows and close doors to let moisture escape and prevent it from spreading through the house.
  • Slightly open your bathroom window after having a bath or shower and, if possible, use an extractor fan for about 20 minutes.

Throughout your home

  • Ventilation removes moist air from your home and replaces it with drier air from outside. Try opening interior doors as well as an upstairs and downstairs window for 30 minutes a day to cross-ventilate your home.
  • Hang your clothes outside to dry or in a bathroom with the door closed and a window slightly open or an extractor fan on – don’t be tempted to put clothes on radiators or in front of a heater.
  • Allow air to circulate around clothes by removing false wardrobe backs or drilling breather holes.
  • Keep a small gap between large pieces of furniture and the walls.
  • Insulate and draught-proof your home (loft and wall insulation are the most effective) to limit cold surfaces and help keep the property warmer – it will also help you save money on your energy bills.
  • Try to keep temperatures in all rooms above 15°C by keeping the heating on at low-to-medium levels all day in cold weather, but remember to keep a check on your meters to see how much it is costing you. Note that heating one room to a high level and leaving other rooms cold will make condensation worse. Therefore it is best to maintain a low-to-medium level of heat throughout the house. If you don’t have heating in every room, keep the doors of unheated rooms open to allow heat to pass into them or use electric heaters on a low setting.

Security tip: make sure accessible windows will not cause a security problem – remember to close them when you go to sleep or if you leave the house!