Decentralized supply and extract unit, with waste heat recovery, designed to be mounted into the external wall of a building, said decentralized supply and extract unit having an indoor module and, adjoining thereto, a heat-exchange module, comprising - a cylindrical heat exchanger with a plurality of heat-exchange air ducts, located along the axis of symmetry of said heat exchanger, said air ducts being cross-sectionally similar and adjoining each other, forming a continuous corrugated volume of heat-exchange segments, - a first separator and a second separator (6, 7) for separating and directing extraction and supply air flows (12, 13) in opposite directions in heat-exchange air ducts, wherein the first separator and the second separator (6, 7) adjoin the heat exchanger, at both end surfaces thereof, and are installed on the axis of symmetry of same, - a first fan and a second fan (8, 9), housings (16, 17) which adjoin the first separator and the second separator (6, 7) respectively, at the ends of the separators facing away from the heat exchanger, and wherein the axis of one of the fans (8, 9) is located parallel with the axis of the other fan (8, 9) and is not aligned with said axis, characterized in that the cylindrical heat exchanger is corrugated; wherein the first separator and the second separator (6, 7) - are designed as separate elements from the heat exchanger, - have a total cross section which corresponds to the total cross section of the heat exchanger, - contain channels, which are an extension of the air ducts of the heat exchanger, forming, together with the air ducts, a continuous volume which is corrugated in shape, - have external end holes, facing away from the heat exchanger, every second external hole being closed off completely, and internal distribution holes, facing towards the axis of symmetry of the heat exchanger, every second hole being closed off completely and being offset by one spacing of channels of the separator, relative to the external end holes. - a cylindrical heat exchanger with a plurality of heat-exchange air ducts, located along the axis of symmetry of said heat exchanger, said air ducts being cross-sectionally similar and adjoining each other, forming a continuous corrugated volume of heat-exchange segments, - a first separator and a second separator (6, 7) for separating and directing extraction and supply air flows (12, 13) in opposite directions in heat-exchange air ducts, wherein the first separator and the second separator (6, 7) adjoin the heat exchanger, at both end surfaces thereof, and are installed on the axis of symmetry of same, - a first fan and a second fan (8, 9), housings (16, 17) which adjoin the first separator and the second separator (6, 7) respectively, at the ends of the separators facing away from the heat exchanger, and wherein the axis of one of the fans (8, 9) is located parallel with the axis of the other fan (8, 9) and is not aligned with said axis, characterized in that the cylindrical heat exchanger is corrugated; wherein the first separator and the second separator (6, 7) - are designed as separate elements from the heat exchanger, - have a total cross section which corresponds to the total cross section of the heat exchanger, - contain channels, which are an extension of the air ducts of the heat exchanger, forming, together with the air ducts, a continuous volume which is corrugated in shape, - have external end holes, facing away from the heat exchanger, every second external hole being closed off completely, and - are designed as separate elements from the heat exchanger, - have a total cross section which corresponds to the total cross section of the heat exchanger, - contain channels, which are an extension of the air ducts of the heat exchanger, forming, together with the air ducts, a continuous volume which is corrugated in shape, - have external end holes, facing away from the heat exchanger, every second external hole being closed off completely, and internal distribution holes, facing towards the axis of symmetry of the heat exchanger, every second hole being closed off completely and being offset by one spacing of channels of the separator, relative to the external end holes.