Condensation occurs when warm, moisture-laden air meets a cool surface such as glass, mirrors, tiling and toilet cisterns. In the winter, colder outside temperatures combined with more heating inside homes will result in larger amounts of condensation.
All air contains water vapour, but the amount of water air can hold is determined by the temperature of that air. This ratio is called the ‘relative humidity’.
Hot air is able to carry much more moisture than cold air, so as the temperature of air rises it is able to hold a greater volume of water. Water vapour is created in many ways just by everyday living. Breathing, washing, bathing, cooking, drying clothes inside and using liquid paraffin or bottled gas room heaters will all create moisture in the air. The more people living in the household and the more of these activities taking place will increase the likelihood of condensation.
Once the air is saturated with water vapour (at a given temperature) it will deposit beads of water (condensation) onto any surface that is cold enough. The temperature of the surface at which this moisture will form is called the ‘dew point’. (For example, when cooking a roast or running a bath with the window closed condensation will build up on the glass and walls, open the window to create a circulation of new air and they will clear).
