Energy consumption for these appliances is measured in kilowatt-hours (kWhs). The more energy an appliance consumes, the more it will cost to operate. One kilowatt-hour (kWh) is the amount of electrical energy supplied by one kilowatt over a one-hour period. It is the basic unit of measurement for electrical energy. Electricity bills are based in part on the number of kilowatt-hours a customer uses during a billing period. These consumption figures do not include the cost of water..