A hybrid heating system, which includes o a geothermal circuit (50, 52, 54) as a primary heat source o a heat pump, including a heat collector circuit and a heat emitter circuit which emits heat at a high temperature o an intake air device which is connectable in heating/cooling operation to a selected side of the heat pump to operate in a selectable manner for the heating or the cooling of the intake air, o an exhaust air device with heat recovery, and an exhaust air device and the geothermal circuit (50, 52, 54) are connected to the collector circuit of the heat pump, and the intake air device is connected in a selectable manner to the heat emitter circuit or to the heat collector circuit of the heat pump characterized in that o the intake air device is connected directly to the collector circuit and indirectly to the heat emitter circuit via a heat exchanger, o the intake air device and/or the exhaust air device as opposite heat exchangers, is a multi-layer cross-flow heat exchanger with a high coefficient of performance, in such extent an exhaust flow of fluid of the heat exchanger can be utilized in a opposite heat exchanger or in the geothermal circuit during at least a part of the year, so that o the exhaust flow of the intake air device can be heated directly by the geothermal circuit (50, 52, 54) or by the exhaust air device, or o the exhaust flow of the exhaust air device can be heated directly by a supply flow of the geothermal circuit (50, 52, 54) or the intake air device, and o the heat pump is layered and comprises two or more units that are adapted to operate in series together or in small groups. o a geothermal circuit (50, 52, 54) as a primary heat source o a heat pump, including a heat collector circuit and a heat emitter circuit which emits heat at a high temperature o an intake air device which is connectable in heating/cooling operation to a selected side of the heat pump to operate in a selectable manner for the heating or the cooling of the intake air, o an exhaust air device with heat recovery, and o the intake air device is connected directly to the collector circuit and indirectly to the heat emitter circuit via a heat exchanger, o the intake air device and/or the exhaust air device as opposite heat exchangers, is a multi-layer cross-flow heat exchanger with a high coefficient of performance, in such extent an exhaust flow of fluid of the heat exchanger can be utilized in a opposite heat exchanger or in the geothermal circuit during at least a part of the year, so that o the exhaust flow of the intake air device can be heated directly by the geothermal circuit (50, 52, 54) or by the exhaust air device, or o the exhaust flow of the exhaust air device can be heated directly by a supply flow of the geothermal circuit (50, 52, 54) or the intake air device, and o the exhaust flow of the intake air device can be heated directly by the geothermal circuit (50, 52, 54) or by the exhaust air device, or o the exhaust flow of the exhaust air device can be heated directly by a supply flow of the geothermal circuit (50, 52, 54) or the intake air device, and o the heat pump is layered and comprises two or more units that are adapted to operate in series together or in small groups.