General information on cooker bonnets (also applies to other manufacturers)

How much power should an extractor bonnet have?

An extractor bonnet should exchange the air in the kitchen approx. 12 times per hour.
Length x width x height x 12 = cbm/h e.g. kitchen 3x3 metres and 2.5 metres high = 22.5 m3 times 12 = 270cbm/h

How much capacity fits through which exhaust system?

100 mm diameter approx. 400 cbm/h (increased running noise)
125 mm diameter round approx. 650 cbm/h
150 mm diameter approx. 800 cbm/h

Where can performance losses occur?

Wall box with movable louvre dampers approx. 3% power loss.
Wall box with rigid cover up to 70% power loss (increased running noise)
per metre of exhaust duct approx. 3% loss of performance
per bend (rounded on both sides) approx. 5% power loss
per bend (with 90° edge on one side) approx. 40% power loss

The values must always be added together:
e.g. cross-section 100mm = 400 cbm/h
Wall box with rigid cover - 70%
2 metre air duct - 6%
Possible exhaust air capacity approx. 112.8 cbm/h

Under these circumstances, the unit will be very noisy and will not function properly.

When operating with an activated carbon filter, the specified output is reduced by approx. 10% and the unit becomes approx. 10% louder.