PURPOSE: To provide an electric warm water heater having a circuit configuration which can switch a heater capacity for heating water in a hot water storage tank to suitable bathing temperature.

CONSTITUTION: The electric warm water heater comprises connecting circuit switching means having a circuit configuration connected with two switching units 10, 11, two heaters 2, 3 and a power source 5, wherein a heater capacity can be switched from 'OFF' to 'maximum' at four stages and power consumption is so reduced as not exceed contract demand power in the case of simultaneous use with other electric unit to heat water in the tank to a suitable temperature. In a 'time zone energy charge rate' system, power consumptions of heaters in daytime and midnight energy time zones can be altered to heat the water in the tank to the suitable bathing temperature. Thus, even if the machine is used simultaneously with other electric unit, the water in the tank can be heated to the suitable bathing temperature without exceeding contract demand power.