A hybrid thermal plant comprising: a boiler provided with a burner, a boiler supply conduit supplied with technical water heated by the burner, and a boiler return conduit; a heat pump provided with a heat pump supply conduit supplied with technical water heated or cooled, directly or indirectly, by the heat pump, and a heat pump return conduit; an interface module comprising: • a first inlet coupled to the heat pump supply conduit configured to receive technical water heated by a heat pump; • a second inlet coupled to the air-conditioning return conduit configured to receive return technical water from an air-conditioning plant; • a first outlet coupled to the boiler return conduit configured to supply return technical water to the boiler; • a second outlet coupled to the heat pump return conduit configured to supply return technical water to the heat pump; characterized in that the interface module being configured so as to selectively connect the first inlet with the first outlet and/or the second inlet with the second outlet or the second inlet with the first outlet on the basis of the operative conditions of the boiler and of the heat pump; the interface module comprising a tank provided with a separating septum adapted to divide the tank into a first chamber in communication with the first inlet and the first outlet, and a second chamber in communication with the second inlet and the second outlet. a boiler provided with a burner, a boiler supply conduit supplied with technical water heated by the burner, and a boiler return conduit; a heat pump provided with a heat pump supply conduit supplied with technical water heated or cooled, directly or indirectly, by the heat pump, and a heat pump return conduit; an interface module comprising: • a first inlet coupled to the heat pump supply conduit configured to receive technical water heated by a heat pump; • a second inlet coupled to the air-conditioning return conduit configured to receive return technical water from an air-conditioning plant; • a first outlet coupled to the boiler return conduit configured to supply return technical water to the boiler; • a second outlet coupled to the heat pump return conduit configured to supply return technical water to the heat pump; characterized in that the interface module being configured so as to selectively connect the first inlet with the first outlet and/or the second inlet with the second outlet or the second inlet with the first outlet on the basis of the operative conditions of the boiler and of the heat pump; the interface module comprising a tank provided with a separating septum adapted to divide the tank into a first chamber in communication with the first inlet and the first outlet, and a second chamber in communication with the second inlet and the second outlet. • a first inlet coupled to the heat pump supply conduit configured to receive technical water heated by a heat pump; • a second inlet coupled to the air-conditioning return conduit configured to receive return technical water from an air-conditioning plant; • a first outlet coupled to the boiler return conduit configured to supply return technical water to the boiler; • a second outlet coupled to the heat pump return conduit configured to supply return technical water to the heat pump; characterized in that the interface module being configured so as to selectively connect the first inlet with the first outlet and/or the second inlet with the second outlet or the second inlet with the first outlet on the basis of the operative conditions of the boiler and of the heat pump; the interface module comprising a tank provided with a separating septum adapted to divide the tank into a first chamber in communication with the first inlet and the first outlet, and a second chamber in communication with the second inlet and the second outlet.