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Condensation Explained

What is condensation ?

Condensation is the process by which water vapor in the air is changed into liquid water.

Condensation generally occurs in the atmosphere when warm air rises, cools and loses its capacity to hold water vapor. The water vapor condenses on a cool surface to form liquid water. Condensation is crucial to the water cycle because it is responsible for the formation of clouds. Clouds produce rain, the primary way water returns to the surface. In short, condensation occurrs naturally in our environment.

We don't have to look at something as far away as a cloud to observe condensation; for many of us condensation is a problem in our homes.

Condensation in the home

Condensation affects new and old buildings alike. It is one of the most misdiagnosed forms of dampness reported in properties - often diagnosed as penetrating or rising damp.

As properties have become better heated and insulated the instances of condensation forming are on the increase. First evidence of condensation may be water droplets forming on the inside of the window pane, because the glass has a lower temperature than the fabric of the wall. Please remember the windows are not the cause of the condensation, they are merely an indication of a condensation problem.

A family of four in a three-bedroom property can generate as much as 18 gallons of water per week as a result of cooking, bathing or by just keeping house plants. With double glazed windows and doors and no ventilation this moisture becomes trapped within the property and can cause mold growth, commonly seen around windows and external corners of the walls.

There is evidence to suggest that condensation and mould have health implications as well as the fact that it spoils the décor and may be the cause of decay in timbers and window frames.

Interior condensation is more likely in the winter months. This happens when moisture in the air contacts a surface whose temperature is lower than the dew point (the temperature in which air manufactures dew).

Exterior surface condensation usually occurs on sultry, humid summer days. An example would be that moisture forms on the outside of a window in the summer when an air conditioner is being used in the home. This creates a surface temperature of the glass below the dew point.

Can we treat condensation ?

In short the answer is "No". Condensation can only be controlled, but there are some steps that you can take to reduce your indoor humidity level.

One way is to make sure that all appliances requiring a vent (for example clothes dryers) are vented properly. Avoid using gas heaters and install extractor fans. Extractor fans are an excellent way to increase the air flow and reduce humidity if installed correctly. Areas that would profit most would be bathrooms and kitchens.

Another option is to make sure that your home is properly vented. There are a couple of ways to achieve this desired effect. One solution for more severe cases would be to open a window in each room for a short period of time. This is a very temporary solution.

For a more permanent solution the installation of passive vents should be considered to allow the passage of warm moist air out and allow fresh air in without critical heat loss. Alternatively you could consider the use of a dehumidifier.