What's a Watt?

We use electricity to perform many tasks. We use units called watts, kilowatts, and kilowatt-hours to measure the electricity that we use.

A watt is a measure of the electric power an appliance uses. Every appliance requires a certain number of watts to work correctly.

Traditional light bulbs were rated by watts (60, 75, 100), as well as home appliances, such as a 1500-watt hairdryer. A kilowatt is 1,000 watts. It is used to measure larger amounts of electricity.

A kilowatt-hour measures the amount of electricity used in one hour. Sometimes it’s easier to understand these terms if you compare them to water in a pool. A kilowatt is the rate of electric flow, or how fast the water goes into a pool. A kilowatt-hour is the amount of electricity, or how much water is added to the pool. We pay for the electricity we use in kilowatt-hours. Our power company sends us a bill for the number of kilowatt-hours we use every month. Most residential consumers in the United States pay about 12 cents per kilowatt-hour of electricity. In 2010, Idaho residents paid the least for electricity: less than 8 cents per kilowatt-hour. Hawaii residents paid the most: more than 28 cents per kilowatt-hour.

Information provided by Constellation Energy, an Exelon Company.