what is the commercial unit of electrical energy

The commercial unit of electrical energy is the kilowatt-hour (kWh) . It is defined as the energy consumed by an appliance of 1 kW when it is used for one hour. One kilowatt-hour is equivalent to the energy of 1,000 joules used for 3,600 seconds or 3.6 million joules. The SI unit of energy is the joule, but the kilowatt-hour is the commercial unit used to express consumed electrical energy.