Abstract: A method and apparatus for the mechanical ventilation and heating of a premises with improved removal of impurities from air present in the premises. At least one suction extraction device is provided for removing polluted or stale air in a region adjacent to the ceiling of the premises. Pure supply air at a temperature in the region of or exceeding the air temperature of the premises is supplied to the premises in the lower region thereof. The supply air forms a substantially horizontal and vertically narrow air jet for displacement of existing air located in a region proximate the floor. The apparatus (1) includes one low impulse device (10) and one high impulse device (20), in addition to which at least one device (31) is provided for guiding air (supply air) emitted from a fan system to the high impulse device and/or to the low impulse device.