Household hair dryers are used for hair drying and plastic surgery, as well as for drying food and clothing. When the hair dryer is powered on, the motor drives the fan blades to rotate, sucking air in from the air inlet, heating it through the electric heating element, and blowing the hot air out of the air outlet. The hair dryer sends out hot air at different temperatures by adjusting the number of energized electric heating elements, and also adjusts the air supply temperature and air volume by adjusting the applied power supply voltage. The temperature of the sent wind is higher, which increases the temperature of the water, thereby accelerating the evaporation of the water.