Heating control method for reducing flicker disturbances for a heating apparatus of an electrical water heater, having the following steps: S1: setting a target temperature; S2: detecting water inlet temperature of the water flowing into the heating apparatus and a water outlet temperature of the emerging water; S3: calculating the output power P required for heating based on the detected water inlet temperature and water outlet temperature and the target temperature that has been set, wherein the output power P required for heating is the full heating power of the heating apparatus P1 multiplied by a percentage Q%; S4: converting the output power P into a duty cycle combination of PWM signals, wherein a duty cycle combination is a combination of - a first number of PWM control signal cycles having a first duty cycle from a first subgroup of PWM signals having a first cycle duration and - a second number of PWM control signal cycles having a second duty cycle from a second subgroup of PWM signals having a differing, second cycle duration, wherein the PWM control signal cycles have a cycle duration of 2, 3 or 4 half-waves and are composed of high and low levels, wherein a change from the low level to the high level and vice versa is effected only at a zero crossing of the voltage controlling the heating apparatus, so that a clock period of switching the PWM signals of the duration of the half-cycle is obtained, such that the percentage Q% is the sum of the first number multiplied by the first duty cycle and the second number multiplied by the second duty cycle, divided by the sum of the first and second number; and generating the respective number of high clock pulses and low clocks of a modulation signal on the basis of the duty cycle combination of PWM signals; S5: controlling the heating process on the basis of the respective number of high clocks and low clocks of the modulation signal; S6: determining whether there is a stop command; if so, terminating the heating process; if not, returning to step S2. S1: setting a target temperature; S2: detecting water inlet temperature of the water flowing into the heating apparatus and a water outlet temperature of the emerging water; S3: calculating the output power P required for heating based on the detected water inlet temperature and water outlet temperature and the target temperature that has been set, wherein the output power P required for heating is the full heating power of the heating apparatus P1 multiplied by a percentage Q%; S4: converting the output power P into a duty cycle combination of PWM signals, wherein a duty cycle combination is a combination of - a first number of PWM control signal cycles having a first duty cycle from a first subgroup of PWM signals having a first cycle duration and - a second number of PWM control signal cycles having a second duty cycle from a second subgroup of PWM signals having a differing, second cycle duration, wherein the PWM control signal cycles have a cycle duration of 2, 3 or 4 half-waves and are composed of high and low levels, wherein a change from the low level to the high level and vice versa is effected only at a zero crossing of the voltage controlling the heating apparatus, so that a clock period of switching the PWM signals of the duration of the half-cycle is obtained, such that the percentage Q% is the sum of the first number multiplied by the first duty cycle and the second number multiplied by the second duty cycle, divided by the sum of the first and second number; and generating the respective number of high clock pulses and low clocks of a modulation signal on the basis of the duty cycle combination of PWM signals; - a first number of PWM control signal cycles having a first duty cycle from a first subgroup of PWM signals having a first cycle duration and - a second number of PWM control signal cycles having a second duty cycle from a second subgroup of PWM signals having a differing, second cycle duration, such that the percentage Q% is the sum of the first number multiplied by the first duty cycle and the second number multiplied by the second duty cycle, divided by the sum of the first and second number; and generating the respective number of high clock pulses and low clocks of a modulation signal on the basis of the duty cycle combination of PWM signals; S5: controlling the heating process on the basis of the respective number of high clocks and low clocks of the modulation signal; S6: determining whether there is a stop command; if so, terminating the heating process; if not, returning to step S2.