| 摘要 |
PROBLEM TO BE SOLVED: To effectively use heat of a heating medium in which heat is accumulated, promote efficient use of an auxiliary heat source side and suppress increase in pressure loss when an auxiliary heat source is used.SOLUTION: This water heater includes: a first heat exchange means (first heat exchanger 4) exchanging heat between a heating medium and supply water; a second heat exchange means (second heat exchanger 6) exchanging heat between heat of the auxiliary heat source (auxiliary heat source device 38) and the supply water; and a control means (control part 8). When a hot water supply target temperature is achieved by the heat exchange by the first heat exchange means, heat exchange is performed only by the first heat exchange means. When the hot water supply target temperature cannot be achieved by the heat exchange only by the first heat exchange means, heat exchange is performed by both of the first heat exchange means and the second heat exchange means or only by the second heat exchange means. |
