HOT WATER SUPPLY SYSTEM

PROBLEM TO BE SOLVED: To improve the heating efficiency of a hybrid hot water supply system which includes: a low speed heater for heating water using heat quantity which atmosphere has; a hot water storage tank for storing hot water heated by the low speed heater; and a rapid heater heating water flowing in a hot water passage from the hot water storage tank.SOLUTION: The hybrid hot water supply system includes: a hot water filling route 50 which branches from a mixed hot water route 34b passed through the rapid heater 40 and leads to a bath tub 64; and a stop valve 52 for opening and closing the hot water filling route. The hybrid hot water supply system performs: (1) processing of monitoring the occurrence of a phenomenon in which the temperature of hot water discharged from the hot water tank to the hot water route 34a becomes below a hot water filling set temperature; (2) processing of determining whether the whole quantity of the hot water discharged from the hot water tank flows in the hot water filling route 50 or not when the phenomenon in (1) occurs; and (3) processing of closing the stop valve 52 when the whole flows in (2) and starting the operation of the rapid heater 40 when not the whole flows.