What is Condensation?

Condensation is the reverse of evaporation; it is the process where water vapour becomes liquid. It can happen in either of two ways:

  • The air is already saturated and cannot hold any more water or
  • The air is cooled to its dew point

In the winter months, the amount of moisture in the inside air (humidity) is often higher and thus less can be absorbed. With the increase in activities that we do – such as leaving windows closed and drying clothes indoors – all contribute to generating more moisture, which makes condensation more prevalent in the colder months.

The dew point is the temperature at which condensation happens. Think of all the early mornings when you have seen dew on the grass or the windscreen of your car; the air temperature can fluctuate above and below the dew point naturally and perhaps the most obvious is when the temperature drops overnight and then starts to warm again as morning approaches. When warm moisture is released into the air and it then comes into contact with a colder surface, it cools quickly, releasing the water which then turns to water droplets – just like what you see happen to your glass (the cold surface) when enjoying an ice-cold drink on a hot summer’s day.

What are the main contributors to condensation?

Anything that adds moisture to the air can contribute to condensation – even breathing adds vapour to the air around us. Think of what you do on a day-to-day basis, from daily showers to regularly boiling the kettle, from cooking on the hob to drying clothes inside. All of these are contributors to excess moisture in the air, and these are only the things we actually do. There are still other contributing factors such as poor ventilation and poor air circulation.

Interesting fact:
Too many household plants can raise humidity levels, but there are certain plants such as the Peace Lily and English Ivy that can actually help reduce it.

So how can I reduce Condensation?

The way to beat condensation is by reducing the amount of excess moisture in the air and by keeping surfaces at a consistent temperature above the dew point.

The following tips should help reduce condensation in your home or workplace.

  • When cooking, ensure that extractor fans are used and lids are put on saucepans. If you do not have an extractor fan, open a window slightly.
  • Keep a window ajar and the door closed when boiling the kettle and washing up.
  • Always use an extractor fan when bathing or showering and keep it running for a little while afterwards if there is still a lot of steam in the room. If you do not have an extractor fan, open the window.
  • Keep doors closed and windows open when showering and cooking – this will help prevent the vapour from travelling to other rooms.
  • Ensure that your walls are properly insulated; this will help keep them above dew point and prevent condensation forming.
  • Ensure that windows are regularly opened to help increase airflow and circulation.
  • Dry clothes outside wherever possible but if they are dried indoors, close the door to the room and keep the window open slightly. However, never put wet clothes on radiators.
  • Avoid placing large furniture against an external wall, but if you have to, ensure that there is air space behind it to enable adequate airflow.
  • Insulate pipes.
  • Keep a consistent temperature within your home / building, even in rooms which are not being used.
  • Where available, keep trickle vents on windows open.
  • Do not block or remove air vents as this will prevent air circulation and ventilation.
  • Be careful when draught-proofing rooms which already suffer from condensation – you could inadvertently make it worse by reducing air circulation.
  • Heat the house a little bit more; a warmer house is less likely to suffer with condensation.
  • Improve windows from single glazing to double glazing; double glazing holds the warmth more, helping to keep them above dew point.

How much moisture should there be in the air?

A certain degree of moisture (humidity) in the air is crucial for optimum health – not only for you but also your building, whether that be your home, place of work or even a garden shed. It is recommended that the relative humidity should sit between 40% – 50% for all year round comfort. It is possible to measure the humidity levels yourself, or you can enlist the help of professionals to carry out an extensive moisture survey.

In our next blog in the series, we take a closer look at humidity and ways to both increase and decrease it as necessary.