The invention relates to fan units for ventilators, in particular for CPAP-apparatus. The fan units comprise a housing, a motor having a stator and a rotor, with the stator being affixed to the housing, and an impeller affixed to the rotor. According to an embodiment the motor is positioned in the suction area of the impeller and the housing forms a suction channel extending helically about the motor axis and being arranged such that the sucked air is accelerated in the direction of rotation of the motor. According to another embodiment the housing in the proximity of the fixtures of the motor is formed such that the housing acts as spring element itself. According to another embodiment a tissue is provided in the fan unit through which the air flows after its compression by the impeller. According to another embodiment a suction port is affixed on the outside of the housing of the fan unit, and a tissue for sound damping is provided in the transition region between the suction port and a suction channel formed by the housing.