Atag WS9111MRL Mode D'emploi page 69

EXTRACTION SYSTEM AND ELECTRIC VALVE
Your cooker hood is fitted with a long-life odour/fine particle filter and
is quieter and more energy-efficient than a conventional cooker hood.
During normal or extended periods of cooking, almost all odours and
fumes will be eliminated. Thanks to the recirculation system, not all the
air will disappear outside. This is because some of the extracted air will
be returned to the kitchen after filtration. This means you will consume
less energy.
EN 7