The Great Escape
Moisture content will quickly build up if confined, especially when generated in the kitchen and bathroom. It helps the situation if there is an opening window to the outside where moisture could escape and be replaced by fresh air. Unfortunately, this is not always a practical solution mainly because of the lack of control. Additionally, if the wind just happens to be blowing in the wrong direction having a window open on a windy day can be more of a hindrance than help. Obviously, an alternative controllable method of condensation control is required, namely, by means of an extractor fan.
The Good Old Days?
The fact that the modern home seems more prone to condensation is no coincident. Everything today is designed to fit better. Modern Upvc windows and doors have draught proofing seals built-into their design, modern double-glazed timber windows and doorframes also have seals inserted into the frames when manufactured and cavity walls are now filled with insulation material. All these features certainly produce draught-proof and warmer homes; unfortunately, this is often at the expense of required ventilation.
By contrast, in the homes of old, it was a different story; curtains were often draped over doorways, and windows to form a barrier from draughts. Another feature of the older house was the fireplace/flues, very often in each room, including the bedrooms. This combination of draughts and ventilation (via the flues) provided a good means of air changes and ventilation.
I'm not suggesting here that you move out of your draught-proof home, but this does go a long way to illustrate the fact that ventilation and regular air changes are an important factor in condensation control.
As mentioned above, of all the rooms in the home there are two which are responsible for generating most moisture, the kitchen and the bathroom, and the most effective method known of removing the vapour in both cases is by fitting an extractor fan.
To control the removal of moisture and at the same time minimise heat loss in the kitchen and bathroom, the solution is an extractor fan fitted to a window, ceiling, outside wall or a ducted system. Extractors come in a variety of sizes to meet the needs of most applications and choosing the right one is dependant on a number of factors. Careful consideration should be given to the extractor's ability in removing a measured amount of air in a given amount of time in relation to the room's size. Rushing out and purchasing a fan labeled 'Bathroom fan', could prove to be an unwise move.
Centrifugal fans are suitable for greater airflow resistance, that is, designed to be used within a ducted system.
Axial Fans are the type designed to fit on a panel, wall mounted or on a window panel. They are designed to move air over a short distance. They would not normally be used in a ducted system.
With an extractor fitted, doors closed, the house fitted with a good draught proofing system and the air being extracted from the room at a measured rate, consideration should be given to air replacement. 'Short Circuiting' is a situation, where the air that is being removed, cannot be replaced at the same rate, resulting in the extractor loosing its ability to extract and function effectively. To overcome this problem, adequate air vents should be installed, which will allow constant air supply into the house/rooms, while the extractor takes the unwanted air outdoors.
Thought should also be given to the position of air vents in relation to the point of extraction and should be fitted in strategically positioned locations that would benefit the overall air flow/ventilation system. This is best done by placing air vents on the opposite side of the room to where the extractor is located, close to the bottom of an internal door to the kitchen for example. Not only does this provide the necessary air replacement, it also benefits air circulation to the whole room, by drawing the air across it.
Extractor fans in the Kitchen