Patent ID: 8919296

Claim:
A hot-water supply system comprising: a first tank for storing hot water for heating; a second tank for storing hot water to be supplied to a hot-water tap, the second tank being accommodated in or mounted to the first tank such that at least a part of the second tank is exposed to the inside of the first tank; a heater circulation path for supplying the hot water of the first tank to a heater and returning the hot water from the heater to the first tank; a first path including a first heat transfer portion surrounding the part of the second tank exposed to the inside of the first tank, the first path connecting the first tank to the heater circulation path so that the hot water of the first tank can be supplied to the heater through the first heat transfer portion; and a second path including a second heat transfer portion disposed along the first heat transfer portion, an inlet of the second path, and an outlet of the second path, wherein each of the inlet and the outlet of the second path is positioned in the second tank, the second heat transfer portion of the second path is disposed outside the second tank, and the second path is configured to form a circulation path in which the hot water stored in the second tank is allowed to flow out of the second tank through the inlet of the second path, to flow into the second heat transfer portion, to exchange heat with the hot water in the first heat transfer portion at the second heat transfer portion, to be directed toward the outlet of the second path from the second heat transfer portion, and to flow into the second tank from the outlet of the second path.