When ducting mode is selected for the
cooker hood, there is a need to open a hole on the wall above the hood and install a ducting hose to evacuate what is being extracted up by the hood.
Whereas there is no need to install a ducting hose for using the cooker hood with recirculation mode. The air which is extracted up by the hood is being filtered using the grease filter and active carbon filter and recycled back into the kitchen.