An arrangement for heat exchangers of a district-heating system of a building, wherein the arrangement includes • a domestic-water heat exchanger, through which district-heating water is conducted and which is configured to deliver heat to domestic water, and which is dimensioned for a selected rated inlet temperature of the district-heating water, • a control valve of the domestic-water heat exchanger for controlling the flow rate of the district-heating water to the domestic-water heat exchanger, • a domestic water circuit, wherein hot water entering the circuit is heated by means of the domestic-water heat exchanger and hot circuit water returning from the circuit is conducted to the domestic-water heat exchanger, • a separate circuit-water heat exchanger, through which district-heating water is conducted and which is configured to deliver heat to heat the hot circuit water, and which is dimensioned for a selected rated inlet temperature of the district-heating water, • a control valve of the circuit-water heat exchanger for controlling the flow rate of district-heating water conducted to the circuit-water heat exchanger, • a temperature sensor for hot circuit water and a temperature sensor for hot water, • control devices for controlling the flow rate of district-heating water in a selected part of the arrangement according to a pre-set program, which control devices are configured at least to control an opening degree of the control valve of the domestic-water heat exchanger and an opening degree of the control valve of the circuit-water heat exchanger on the basis of readings of the temperature sensor for hot circuit water and of the temperature sensor for hot water, characterized in that • the circuit-water heat exchanger is of lower power than the domestic-water heat exchanger, • the control devices are configured to heat the domestic water in the circuit-water heat exchanger to a setpoint temperature 1 - 5 °C, advantageously 2 - 4 °C, higher than the domestic-water heat exchanger preventing the control valve of the domestic-water heat exchanger to open when domestic water is not being used, and • the geometric parameters of the heat exchanger are so configured that the rated inlet temperature of district-heating water for the circuit-water heat exchanger is 2 - 10 °C, advantageously 4 - 6 °C, lower than the rated inlet temperature of district-heating water for the domestic-water heat exchanger. • a domestic-water heat exchanger, through which district-heating water is conducted and which is configured to deliver heat to domestic water, and which is dimensioned for a selected rated inlet temperature of the district-heating water, • a control valve of the domestic-water heat exchanger for controlling the flow rate of the district-heating water to the domestic-water heat exchanger, • a domestic water circuit, wherein hot water entering the circuit is heated by means of the domestic-water heat exchanger and hot circuit water returning from the circuit is conducted to the domestic-water heat exchanger, • a separate circuit-water heat exchanger, through which district-heating water is conducted and which is configured to deliver heat to heat the hot circuit water, and which is dimensioned for a selected rated inlet temperature of the district-heating water, • a control valve of the circuit-water heat exchanger for controlling the flow rate of district-heating water conducted to the circuit-water heat exchanger, • a temperature sensor for hot circuit water and a temperature sensor for hot water, • control devices for controlling the flow rate of district-heating water in a selected part of the arrangement according to a pre-set program, which control devices are configured at least to control an opening degree of the control valve of the domestic-water heat exchanger and an opening degree of the control valve of the circuit-water heat exchanger on the basis of readings of the temperature sensor for hot circuit water and of the temperature sensor for hot water, characterized in that • the circuit-water heat exchanger is of lower power than the domestic-water heat exchanger, • the control devices are configured to heat the domestic water in the circuit-water heat exchanger to a setpoint temperature 1 - 5 °C, advantageously 2 - 4 °C, higher than the domestic-water heat exchanger preventing the control valve of the domestic-water heat exchanger to open when domestic water is not being used, and • the geometric parameters of the heat exchanger are so configured that the rated inlet temperature of district-heating water for the circuit-water heat exchanger is 2 - 10 °C, advantageously 4 - 6 °C, lower than the rated inlet temperature of district-heating water for the domestic-water heat exchanger.