What is the usefull and wasted energy in a hair dryer?

The useful energy in a hair dryer is the electrical energy that is converted into heat energy to dry and style hair. The wasted energy in a hair dryer is the energy lost to friction and air resistance, as well as any energy that is not effectively transferred to the hair. This wasted energy may manifest as noise, heat loss to the surrounding environment, or inefficiencies in the motor and heating elements.