Kilowatt-hour

The U.S. Energy Information Administration says utilities generally measure electricity in kilowatthours, and one kWh is one kilowatt for one hour. Its example: a 40-watt bulb used for five hours uses 200 watthours, or 0.2 kWh. Oncor defines energy as the measure of how much electric power is provided over time.

Wattage is the rate and kWh is the total, like speed and distance. The meter in the meter base counts kWh. A sudden jump in use can mean a failing appliance or a wiring fault, and a licensed electrician can help trace it. See the home electrical safety checklist.