Apparatus for controlling hot water washing of washing machine and method thereof

A method of supplying wash water to a washing machine including a water supply device, a heater, a sensor and a controller, the method comprising:

• setting a washing condition;
• supplying water to the washing machine according to the set washing condition;
• determining whether a water level in the washing machine is at a heating water level;
• heating the water in the washing machine if the water level is at the heating water level;
• determining whether the water level in the washing machine is at a washing water level associated with the set washing condition;
• when the water level is at the washing water level, determining whether a water temperature of the water in the washing machine is at a heating temperature associated with the set washing condition;
• and
• after the temperature of the water in the washing machine is at the heating temperature, turning off the heater, and then initiating a wash cycle associated with the set washing condition, wherein heating the water in the washing machine comprises turning on the heater as soon as the heater is completely submerged in the water supplied to the washing machine, and continuing to supply water to the washing machine after the water level is at the heating water level while heating the water.