Why is Condensation a Bad Thing

Why is Condensation a Bad Thing

By Ruth MacEachern

Product Manager

Condensation is caused when water vapour is released from the air and becomes a liquid. It is formed on cooler surfaces in your home including windows, tiles, and on exterior walls.

The air in homes can hold a surprising amount of water vapour – at 20C – normal room temperature, a cubic metre of air can hold just over 17ml of water. In an average 12m² room, this means that the air is carrying approximately 450ml of water. When the temperature drops, the amount of water vapour that the air can carry falls considerably. At 15C – a normal typical night-time temperature, the moisture capacity of the air in the same room falls to under 340ml. This means that about a glass of water will be distributed across cool surfaces in the room.

What Humidity Level is Healthy

Most of the time, the amount of moisture carried by the air in our homes remains below the maximum, and some level of humidity is important. According to the Mayo Clinic, humidity levels between 30-50%. This level is below that at which condensation will normally form during day-to-day changes in temperature.

The actual humidity levels in our homes can change considerably over the course of a day, and even from room to room. Wet rooms such as bathrooms and kitchens can have large shifts in the humidity levels when they are in use. A bath can release a large amount of steam into the air – as can cooking – and if clothes are dried on radiators, this can also release water vapour into the air.

Unless this moist air is removed from the house, the humidity levels can quickly build up to the point where condensation forms.

While condensation itself isn’t a major issue – beyond the need to wipe down windows on cool mornings – it can lead to bigger problems in your home including damp and mould.

What Are the Risks of Damp?

On windows and tiles, condensation will remain on the surface and can be wiped away, however on porous materials such as wood, plasterwork, or furnishings, the condensation can soak through and build up to form damp.

In wooden window frames or doors, damp can attack the wood fibres, weakening them and allowing microbes to start digesting the wood itself.  This quickly leads to rot where the structure of the wood will start to crumble and weaken.

In windows, rotten wood can allow draughts to get in and make panes loose, while doors may become warped and difficult to close. In severe cases of damp that affect the framing of the house, serious structural problems can be caused.

Aside from window frames, one of the most common places to see damp as a result of condensation is in the plasterwork on external walls.  These walls are typically colder surfaces and attract condensation which soaks into the plaster. The first sign of condensation may be stains on the wall where the plaster colouring seeps through the paint. Peeling paint and wallpaper will soon follow, and eventually the plaster itself will begin to crumble.

Repairing the damage caused by damp from condensation can be expensive, and in severe cases, large areas of the home may need to be replastered and windows may need to be replaced.

Unfortunately, damp can create problems for your health too, as an ideal environment for mould to grow.

Read more about Damp here>> (link to damp page)

What Problems Can Mould Cause?

Mould thrives in the damp conditions that develop from condensation. The colonies grow quickly and create easy to spot patches on the walls which appear black or very dark green.

As mould grows, it releases spores which can be an irritant for people with respiratory disorders. Some species of mould including Stachybotrys Chartarum (also known as toxic black mould) are particularly dangerous, releasing chemicals known as mycotoxins which can cause a very severe allergic repsonse.

Except for Toxic Black mould, which needs to be professionally removed, most mould can be cleaned using dilute bleach or fungicide, however unless the root cause of the damp is removed, the mould will come back quickly.

Read more about how to Clean Mould >> 

What You Can Do to Stop Condensation

There are several ways to reduce condensation in your home including using pan lids when cooking, ensuring that windows are open during the day, and avoiding drying clothes indoors, but the only way you can get rid of condensation for good is to improve the ventilation in your home. Modern extractor fans in bathrooms and kitchens will remove the warm moist air and prevent it getting into the rest of your home where it can cause condensation.

More effective whole house ventilation systems such as PIV (Positive Input Ventilation) can be installed in homes and ventilate the whole house through a central unit installed in the loft. These ensure better quality air in all rooms.

Find out which ventilation system is right for you>> 

Find out More

EnviroVent have helped thousands of households to stop condensation and prevent it developing into damp and mould. If you are concerned about the risk to your property from condensation and want to speak to an expert, please contact us today to book a Free home Survey. Our local ventilation specialists can visit your property, identify the sources of condensation, and provide you with advice about the best way to deal with it.

Simply enter your postcode below to find your local specialists.