Kilowatt hour (kWh)

A kilowatt-hour (kWh) is a unit of energy equivalent to one hour (1 kW) of power which is expended for an hour of time. This is a measured consumption of electrical energy which is the equivalent of 1000 watts used steadily for one hour. The kilowatt-hour is rarely used to express energy in any form other than electrical.

For example, a 100-watt light bulb burning for 10 hours, or ten 100-watt light bulbs burning for one hour would use one kilowatt hour of energy.