Extraction or Recirculation?

The decision of whether either extraction or recirculation can be used in your kitchen depends on several different factors. The list gives the most important criteria for consideration when choosing the right mode for you.

Checklist Recirculation Extraction
Not necessary Necessary
Not necessary Necessary
Possible Window contact switch
Not necessary Necessary
Possible Consultation required
Possible Not possible
Not recommended Possible
Not possible Possible
Necessary Not necessary
Necessary Not necessary

Further information on extraction and recirculation

Extraction ducting

Ducting allows odours and moisture to be directed outside. Flow characteristics are affected by the shape and length of the ducting system. In general: round is better than square and the smoother the surface of the ducting, the more efficient the extraction system will be. The cross-section of the ducting must also be suitable for the power of the fan.

If a flat ducting system is used, air deflectors must be used in the bends. 150 mm round ducting can be effectively replaced by a flat ducting system of 89 mm x 222 mm. Longer ducting lengths with several bends can have a negative impact on the efficiency of the rangehood.