What is a kilowatt?

Learn more about the unit of measurement for energy consumption

Posted on Jun 24 2024 in Energy

By Rob Powell

Energy providers and electric bills often reference kilowatts and the cost per kilowatt hour used. While those terms might be familiar, you might occasionally wonder just what is a kilowatt?

The first and perhaps most obvious thing to know is that a kilowatt is a metric unit of power used to measure the rate of energy production or consumption.

One kilowatt is equal to 1,000 watts. As a point of reference, the most common wattage for a light bulb in your living room lamp is 60 watts. Kilo means a thousand and the watt was named after Scottish inventor James Watt, most famous for his work creating a steam engine in the 1760s and 1770s.

Within the electric industry, the kilowatt is used in three key places. The first is in electrical power generation, where power plants convert fuels from coal to natural gas to nuclear power into electrical energy. The plant’s output is usually measured in megawatts, which is 1,000 kilowatts.

Secondly, residential and commercial energy consumption relies on the kilowatt as the unit of measurement to calculate the cost of energy production or consumption.

Thirdly, the kilowatt can be used to compare the energy efficiency of devices. For example, a pair of electric water heaters may have the same power rating, but by comparing the amount of heat generated per kilowatt consumed, we can determine which one is more efficient and cost-effective.

For the consumer, the most relevant aspect of the kilowatt is knowing how it will translate on their monthly bill. That’s where kilowatt hours come in. If a home uses one kilowatt of power in an hour, that is a kilowatt hour.

According to the Energy Information Administration, the average amount of electricity purchased by a U.S. residential electric utility customer was 899 kilowatt hours per month in 2022. In the state of Indiana, the average cost of electricity that year was 11.66 cents per kilowatt hour, a number that has only gone up since.

You can figure out the cost of household appliances with a simple formula — watts multiplied by time divided by 1,000 equals kilowatt hour. In practical terms, a 1,000-watt microwave used 15 minutes per day would be about 7.5 kilowatt hours per month. In other words, that will cost about a dollar on your monthly electric bill.

ROB POWELL is director of systems operations at Daviess-MartinCounty REMC in Loogootee, Indiana.