Condensation occurs when water vapour becomes trapped on a material. In homes, this is usually visible on your window as foggy patches.
Often people make the mistake of assuming that condensation signifies a problem with their window, but this is usually not the case. In fact, condensation on the outside facing window can signal that your windows are well insulated, preventing enough heat from escaping and causing the condensation to evaporate.
Condensation on the inside of your home, however, can be a problem. Whilst small foggy patches in the corner of a window that quickly evaporate will not necessarily be cause for concern, excessive condensation can run off windows and cause damage to timber frames.
One of the main causes of condensation is that water vapour in your home is unable to escape into the outside air. Water vapour is present in just about all types of air, but it can vary in density. Water vapour will naturally try to dilute to an even balance across a body of air; heavier concentrations of vapour will try to disperse into lighter concentrations. The walls and windows of your home prevent the vapour from easily dispersing into the outside air, causing it to build up inside the home.
Human activity contributes greatly towards increasing the amount of water vapour inside the home. Cooking, cleaning, showers, bathing and other various activities all cause humidity. Without proper ventilation, it can build up and cause condensation. Whist water vapour can naturally pass through building materials such as bricks, plaster, wood and mortar to a degree, it cannot pass through glass, which is why you can often see it condensing on your windows. Furthermore, many modern building materials can go further towards sealing the home to prevent heat loss, but at the same time they can prevent water vapour from escaping. Many modern homes are also smaller and trap the same amount of water vapour you would expect in a larger home into a smaller space, increasing the chances of condensation.
Wood has the ability to store up moisture. Many people will see condensation for the first few weeks of winter. This can happen when a home has had its heating off for the summer and moisture has built up in the wood. When the heating is switched back on, the wood begins to dry out releasing more water vapour into a home.
Simple steps can be taken to reduce vapour content in the air and lessen the chances of condensation forming in your home.
- Switching the heating on after a humid summer, and ventilating the home at the same time, will help to dry out any wood and avoid condensation.
- Using extractor fans when cooking helps and ensuring that you have enough ventilation in places such as your bathroom or laundry room, where appliances can add more water vapour to your home.
- Opening doors or windows for a few minutes a day can also help water vapour to escape into the outside air.
It is a good idea to remember that properly installed double glazed windows are not likely be the source of a condensation problem.