STORAGE TYPE HOT WATER SUPPLY APPARATUS

PROBLEM TO BE SOLVED: To prevent wasteful heat radiation from a hot water storage tank because of reheating in the daytime carried out earlier than necessary which results in a prolonged time until hot water is actually supplied.SOLUTION: This storage type hot water supply apparatus includes: the hot water storage tank 1, to which a water supply pipe 2 and a hot water discharge pipe 4 are connected, for storing hot and cold water; a heating means 23 for heating hot or cold water taken out of the lower part of the hot water storage tank 1, and returning the heated water to the upper part of the hot water storage tank 1; and a control means 41 computing the heat quantity required for the next day from the heat quantity used in the past predetermined period, boiling up the required heat quantity in a predetermined time zone, and reheating other than the predetermined time zone when the residual hot water heat quantity in the hot water storage tank 1 fulfills predetermined reheating start conditions when there is the required heat quantity to be reheated which is the required heat quantity not boiled up within the predetermined time zone. The control means 41 computes the degree of dispersion in the heat quantity used for every unit period of the past predetermined period, and changes the predetermined reheating start conditions to delay the timing to start reheating outside the predetermined time zone when the dispersion degree is low.