Installation for preparing hot sanitary water, comprising the following: • a main container for removal of hot sanitary water through an exit for hot sanitary water at the high portion of the main container, • an auxiliary container, having a small volume in relation to the volume of the main container, with an inflow for cold water at the low portion of the auxiliary container, • a connecting line, which opens out (31, 32) into the high portion of the auxiliary container and into the low portion of the main container, • a branch circuit, which connects the low portion of the auxiliary container to the high portion of the main container and is equipped with a heat pump, • a group of temperature sensors (T...), which are connected to a control circuit, wherein the temperature sensors are fitted in the high portion and the low portion of the main container and in the high portion of the of the auxiliary container, wherein the control circuit is connected to the heat pump in order to activate the latter in a manner dependent on the temperatures supplied by the sensors, which temperatures, for their part, depend on the removal of hot sanitary water, characterized by a circuit with a heating boiler which is connected to an exchanger installed in the low portion of the main container, wherein the control circuit is connected to the heating boiler in order to activate the latter in a manner dependent on the temperatures supplied by the sensors, wherein the circuit with the heating boiler comprises a central-heating circuit at a branching point, which central-heating circuit is connected to a feed line of the circuit and, by way of a three-way valve, to a line which is connected to the exchanger of the main container, wherein the central-heating circuit branches off from the feed line. • a main container for removal of hot sanitary water through an exit for hot sanitary water at the high portion of the main container, • an auxiliary container, having a small volume in relation to the volume of the main container, with an inflow for cold water at the low portion of the auxiliary container, • a connecting line, which opens out (31, 32) into the high portion of the auxiliary container and into the low portion of the main container, • a branch circuit, which connects the low portion of the auxiliary container to the high portion of the main container and is equipped with a heat pump, • a group of temperature sensors (T...), which are connected to a control circuit, wherein the temperature sensors are fitted in the high portion and the low portion of the main container and in the high portion of the of the auxiliary container, wherein the control circuit is connected to the heat pump in order to activate the latter in a manner dependent on the temperatures supplied by the sensors, which temperatures, for their part, depend on the removal of hot sanitary water, characterized by a circuit with a heating boiler which is connected to an exchanger installed in the low portion of the main container, wherein the control circuit is connected to the heating boiler in order to activate the latter in a manner dependent on the temperatures supplied by the sensors, wherein the circuit with the heating boiler comprises a central-heating circuit at a branching point, which central-heating circuit is connected to a feed line of the circuit and, by way of a three-way valve, to a line which is connected to the exchanger of the main container, wherein the central-heating circuit branches off from the feed line. characterized by a circuit with a heating boiler which is connected to an exchanger installed in the low portion of the main container, wherein the control circuit is connected to the heating boiler in order to activate the latter in a manner dependent on the temperatures supplied by the sensors, wherein the circuit with the heating boiler comprises a central-heating circuit at a branching point, which central-heating circuit is connected to a feed line of the circuit and, by way of a three-way valve, to a line which is connected to the exchanger of the main container, wherein the central-heating circuit branches off from the feed line.