In order to reduce the difference in stress of the tubes through which heating steam is flowing in the case of heat exchangers where the tubes are concentrated in at least two horizontal bundles and where heating steam flows through the tubes and a power medium flows around the tubes, it is proposed that there are arranged at the intake openings of the tubes (1) through which the heating steam is flowing baffles (3) with different intake profiles (4) in such manner that within each bundle of tubes the intake profiles (4) will become smaller in direction of flow of the power medium to be heated.
