ventilation system, in particular an air conditioning system of a vehicle

The method involves passing an increasing fraction of the circulating air from the vehicle interior (5) through a second circulating air opening (8) of a device with first and second circulating openings and a fan (4) in relation to the volumetric flow passing to the first circulating air opening (7), at least above a definable circulating air volumetric flow threshold value. AN Independent claim is also included for the following: a device for implementing the inventive method.