A hot-water supply system comprising: a compressor for compressing refrigerant; an air heat exchanger for exchanging heat between the refrigerant and air; a first heat exchanger for exchanging heat between the refrigerant and a heat medium; a refrigerant circuit switching valve for switching between a first refrigerant circuit through which the refrigerant compressed by the compressor flows into the first heat exchanger and a second refrigerant circuit through which the refrigerant compressed by the compressor flows into the air heat exchanger; a second heat exchanger for exchanging heat between the heat medium and water; a heat-medium circuit (15, 25, 26, 27, 28, 29) connecting the first heat exchanger to the second heat exchanger; a heat-medium pump for circulating the heat medium in the heat-medium circuit (15, 25, 26, 27, 28, 29); a hot-water storage tank including a lower portion provided with a water outlet, and an upper portion provided with a hot-water inlet at a level higher than a level of the water outlet; a water-feed path connecting the water outlet to the second heat exchanger; a water-return path connecting the second heat exchanger to the hot-water inlet; a water pump for circulating the water in a water circuit formed by the water-feed path, the second heat exchanger, and the water-return path; and control circuitry (9, 16) configured to control a heat accumulating operation for causing hot water flowing out of the second heat exchanger to flow into the hot-water storage tank and a defrosting operation for melting frost sticking to the air heat exchanger, the control circuitry (9, 16) being configured to: in the heat accumulating operation, work the compressor, the heat-medium pump, and the water pump, and circulate the refrigerant through the first refrigerant circuit; in the defrosting operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the second refrigerant circuit; characterized in that the control circuitry is configured to: perform a recovery operation before restarting the heat accumulating operation after the defrosting operation; and in the recovery operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the first refrigerant circuit. a compressor for compressing refrigerant; an air heat exchanger for exchanging heat between the refrigerant and air; a first heat exchanger for exchanging heat between the refrigerant and a heat medium; a refrigerant circuit switching valve for switching between a first refrigerant circuit through which the refrigerant compressed by the compressor flows into the first heat exchanger and a second refrigerant circuit through which the refrigerant compressed by the compressor flows into the air heat exchanger; a second heat exchanger for exchanging heat between the heat medium and water; a heat-medium circuit (15, 25, 26, 27, 28, 29) connecting the first heat exchanger to the second heat exchanger; a heat-medium pump for circulating the heat medium in the heat-medium circuit (15, 25, 26, 27, 28, 29); a hot-water storage tank including a lower portion provided with a water outlet, and an upper portion provided with a hot-water inlet at a level higher than a level of the water outlet; a water-feed path connecting the water outlet to the second heat exchanger; a water-return path connecting the second heat exchanger to the hot-water inlet; a water pump for circulating the water in a water circuit formed by the water-feed path, the second heat exchanger, and the water-return path; and control circuitry (9, 16) configured to control a heat accumulating operation for causing hot water flowing out of the second heat exchanger to flow into the hot-water storage tank and a defrosting operation for melting frost sticking to the air heat exchanger, the control circuitry (9, 16) being configured to: in the heat accumulating operation, work the compressor, the heat-medium pump, and the water pump, and circulate the refrigerant through the first refrigerant circuit; in the defrosting operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the second refrigerant circuit; characterized in that the control circuitry is configured to: perform a recovery operation before restarting the heat accumulating operation after the defrosting operation; and in the recovery operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the first refrigerant circuit. in the heat accumulating operation, work the compressor, the heat-medium pump, and the water pump, and circulate the refrigerant through the first refrigerant circuit; in the defrosting operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the second refrigerant circuit; characterized in that the control circuitry is configured to: perform a recovery operation before restarting the heat accumulating operation after the defrosting operation; and in the recovery operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the first refrigerant circuit. perform a recovery operation before restarting the heat accumulating operation after the defrosting operation; and in the recovery operation, work the compressor and the heat-medium pump while the water pump is stopped and circulate the refrigerant through the first refrigerant circuit.