An apparatus for supplying gas, includes a ventilator having a motor, a rotor having vanes and a volute, a conduit for cooling the motor, and a soundproofing housing containing the ventilator and the conduit. The conduit has a shape similar to the wall of the motor and the volute, thus providing a flow path around the motor and the volute. The conduit also includes two housing portions, one of which includes a set of walls, forming a portion of the soundproofing housing and the conduit, and the other also includes a set of walls, forming the matching portion of the soundproofing housing and the conduit. The portions of the soundproofing housing and the conduit on the same portion of the housing are integral with one another, the two portions being suitable for being assembled together around the ventilator such as jointly to form the conduit and the soundproofing housing.