A heating apparatus includes two heating circuits (3, 4), one for room heating (3) and one for domestic water heating (4). A primary heat exchanger (1) is provided as well as at least one secondary heat exchanger (7), for the room heating as well as a secondary heat exchanger (9) for domestic water heating. A circulation pump (6) is provided as well as a switch-over valve (5) which hydraulically integrates the primary heat exchanger (1) into the first or into the second heating circuit (3, 4). The heating circuit (4) for the domestic water heating, on operation of the heating circuit (3) for room heating, is used as a bypass conduit for the primary heat exchanger (1), wherein the switch-over valve (5) forms the bypass valve or is used as a bypass valve.