Abstract: A blower unit, designed for use for example with air-conditioning plant, has an outer housing with a first aspiration or inlet connection forming part of an aspiration duct for a primary volume flow, and a second aspiration connection forming part of an aspiration duct for a secondary volume flow. The outer housing furthermore has outlet or pressure connections joined up with the primary and with the secondary circuits for the supply of air thereto. In the housing two blower impellers are placed and the outer part of the housing has an adjustable unit which may be moved into different positions of adjustment so that the volume flows incoming at the outlet side of the blower impellers may be directed by different adjustments to the pressure (or outlet) connections as may be desired. The outer housing has two separate spaces in which the two blower impellers are placed which are fixed in an axial direction. Each such blower impeller has an air guiding housing.