Residential Extractor Fan Ancillary Items | Blauberg UK

Fan choice and air circulation calculation

Before choosing a fan define its destination, necessary modifications and, what is important, the power (capacity) of the device.

If the fan is set in the bathroom or lavatory, it is quite possible that you will need a timer that makes the fan operate and turns it off automatically even after you have left the room. Humidity sensor will turn the fan on when the level of moisture exceeds the set one. For kitchen or other premises you can use a fan with pull-cord switch for short-term air extraction.

1. Diameter of the flange that can be installed into your ventilation shaft – 100, 125 or 150 mm.
2. Volume of the room and air exchange per hour.

Along with the above mentioned, the following should be taken into consideration when choosing a fan:

In order to calculate the volume of the room, use a simple formula please: Volume (cub.m.)=length*height*width (m).

For different premises there are different norms for air exchange. Some of them can be found below.

Room type	Square, м2	Air exchange rate per hour	Required capacity, м3/h
Lavatory	4-9	5-9	90-200
Bathroom	8-12	5-9	90-150
Kitchen	8-18	6-12	100-300
Living room/bedroom	12-25	4-8	90-300
Service room, accomodation space	4-8	5-8	90-190