| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that hot water surplus or hot water shortage occur because a heat dissipation loss coefficient is constant for calculating a boiling-up target hot water amount.SOLUTION: A water heater includes: a boiling-up mode selecting means 24 for selecting one of a plurality of boiling-up modes with different day-night operation ratios in a boiling-up operation of boiling hot water in a hot water storage tank 1 with a heating means 8; a boiling-up target hot water amount calculating means 26 for calculating a necessary boiling-up hot water amount on the basis of a hot water use amount in a plurality of days, and also calculating a boiling-up target hot water amount by multiplying the obtained necessary boiling-up hot water amount with a predetermined heat dissipation loss coefficient; and a boiling-up control means 31 for controlling the water heater to boil hot water up to the boiling-up target hot water amount at night or at night and during the day in accordance with the selected boiling-up mode. The boiling-up target hot water amount calculating means 26 varies the predetermined heat dissipation loss coefficient in accordance with the selected boiling-up mode. |
