How to choose the right domestic extractor fan

Selecting the correct extractor fan for a specific ventilation problem need not cause too many headaches. The most important fact to take into consideration is that an extractor fan can only ever bring down the temperature of any given room to ambient outside temperature. If you want to cool down a room, air conditioning or evaporation cooling should be considered.

Extractor fans are used to create air flow through buildings. Increased air flow can solve damp problems. It can also extract unwanted fumes from buildings or provide fresh air where ventilation is poor.

Extractor fans are only efficient when there is adequate fresh air coming into the room. One should always consider the inflow of air into a room when installing an extractor fan. Door louvers or wall louvers usually need to be installed. When small domestic fans are installed, one can undercut the doors of the room to provide enough fresh air.

Manufacturers of extractor fans usually provide air flow specs for their fans. The airflow of a specific fan is measured in cubic meters per hour. This means that the fan moves X cubic meters of air every hour while in operation.

Steps for selecting an extractor fan:

Example: Your bathroom is 3m long X 2m wide X 2.4m high. The volume of the room is  3m X 2m X 2.4m = 14.4m3

Example: Bathrooms usually require between 6 and 10 air changes per hour. If you have a severe damp problem in your bathroom, go for 10 to 15 air changes.

Example:  If you need 15 air changes, simply multiply the volume of the room to be ventilated by the air changes required. 15 air changes X 14.4m3 = 216m3/h.

Example: Choose an extractor fan that can move a minimum of 216m3/h.

Now all you need to do is to decide where to install your extractor fan. Domestic extractor fans can be installed in the ceiling, wall or window. The choice is yours. VentaNation usually advises clients who have damp problems in their bathrooms not to install basic ceiling mounted extractor fans without ducting, because one usually ends up moving the problem from the bathroom to the roof cavity.

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