Which diameter should my ceiling fan have?

The diameter of a ceiling fan is decisive for the amount of exchanged air, think of an airplane propeller, it is exactly the same case. Depending on the size of the room and height of the ceiling a different fan diameter is recommeded.

The bigger the diameter, the more air can be circulated.

This figure should help you find the right diameter for your premises.

Please keep in mind that ceiling fans have a circular area of impact that becomes bigger towards the ground. The pictured recommendations therefore correspond to a square room. As not every room is shaped like a square, longer rectangular rooms should be divided into a smaller amount of squares. This helps to determine the suitable diameter as accurately as possible.

Here’s an example:

Room length: 12m, room width: 4m

It is recommeded to divide it into three squares (4 x 4 m) à 16 m2.

⟶ A room with 3 m ceiling height requires 3 ceiling fans with 103 cm diameter each to guarantee sufficient air circulation inside the room.

Our search filter lets you select the specifications below. However, please keep in mind that the diameter also depends on the room height and not only from the square metre value. In this case the figure shown above is more accurate!

Fan diameter Room size
60-100 cm 5-10 m2
100-119 cm 10-15 m2
120-139 cm 15-25 m2
140-160 cm 25-30 m2
160 cm and above 30 m2 and above

The values stated above apply both to the operating mode in summer that has a cooling effect as well as on the heat recovering feature that recirculates warmth during the heating period. Did you calculate a value at the threshold between two recommended diameters? We recommend going for the bigger model because you can also run it on a slower speed level. Smaller fans usually emit more audible sounds during operation that bigger items as they rotate faster to reach the same amount of circulated air. Particularly in bedrooms you should focus on quiet running.

TDA fans for industrial application can overcome ceilings as high as 10 metres! In case of production facilities and storage rooms measuring 35 m2 and more it is especially important to pay attention to the layout of the room and, if need be, go for several powerful smaller fans than just one big model. The distance between the devices corresponds to the root of surface m2 / required units.

Example: A rectangular warehouse with 200 m2 (root is 14.14) requires 10 TDA fans with 122 cm diameter per 1000 m2 according to the figure on the side, assuming the room height is 6 metres. That means 2 fans will be needed to cover 200 m2.

The distance between the fans therefore equals
14.14 / 2 = 7.07 Meter
measured from the centres of the devices. The distance to the outer wall accounts for half of this value, in this case 3.53 metres.

In order to enjoy constant ventilation in a room without any unpleasant draught caused by too much air speed, we recommend controlling the rotation with a remote control, wall controller or step-transformer, to name but a few. Adequate circuits allow you to control several models at once without difficulty.

A matter of aesthetics

An appealing design is naturally one of the key buying criteria when it comes to interior design at home. Still, try to comply with the guidelines for size, you would not profit at all from a fan that is too powerful or too small. In the first case there is a risk of too much air ciruclation and draught, in the second case the fan might not reach outer areas of the room and its corners.

The recommended diameter seems to be too massive? Slender blades in light colours visually reduce the size.