Abstract: A method and apparatus for heating room space of a building. According to the invention, heat is conveyed from district heating water to a heating liquid of heating circuits for heating the building, tap water and supply air of ventilation. According to the invention, the heating circuits for heating the building and the supply air are connected in series in such a manner that the heating liquid flowing in the piping heats, after passing a heat exchanger, first the heating circuit for heating the building and thereafter the heating circuit for heating the supply air. On account of the invention, the temperature of the district heating return water is lower than in the known apparatuses.

Abstract: Disclosed is a high-pressure centrifugal blower, which comprises an impeller with a back plate and pressure leveling blades secured to the back side of that back plate. The blades extend from the periphery of the impeller over some distance radially inwards. In order to regulate the pressure control clearance between the blades and the back wall of the blower case, control members have been installed between the blades and the back wall of the case.