Abstract: The invention relates to an appliance for heating motor vehicles, mainly buses driven with internal combustion engine, provided with heat accumulator in heat transfer connection with the exhaust pipe of the engine, and in given case with the space to be heated. The essential feature of the invention is that the heat accumulator (5) is directly connected with the extended coolant circuit of the engine (M)--and in case of additional heat extracting medium through the installation of heat exchanger (3), furthermore circulating pump (24) operated independently from the engine (M) is built into the extended coolant circuit.