A kilowatt hour (kWh) is a measure of how much energy you’re using per hour. kW stands for kilowatt, a universal standard for measuring electricity. One kilowatt equals 1,000 watts. The h in kWh stands for hour – a measure of time. The kWh is a unit if energy and your electricity provider charges you for every kWh you use. As an example, a machine that is rated at 3kWh will consume 3000 watts of power per hour. If you were paying 20p per kWh, the machine would cost 60p per hour to run.