What Exactly is a Kilowatt-Hour?

A kilowatt-hour (kWh) is a measure of energy use—it’s the amount of electricity used when a 1,000-watt device runs for one hour.

Your electric bill is based on how many kWh you use each month.

It’s a simple way to track and understand your home’s energy consumption.

On your monthly bills, you're charged for electricity by the kilowatt-hour (kWh). In fact, the average American household uses nearly 900 kilowatt-hours a month, according to the U.S. Department of Energy. Have you ever wondered what a kilowatt-hour is and why you are charged for electricity that way? If so, we've got the answers.

Breaking down kilowatts

Every electrical device has a power rating, which tells you how much power it needs to work. This is given in watts or kilowatts. A kilowatt is equal to 1,000 watts. Kilo is a prefix in the metric system for 1,000. A watt is a tiny unit of electricity named after Scottish inventor and energy pioneer James Watt.

Power ratings for devices can vary widely. Refrigerators can use 300 to 800 watts, depending on their age, capacity and model. TVs can range from 50 to 200 watts, depending on size and type. A typical space heater uses 1,500 watts, although some models may use less.

Calculating kilowatt-hours

So, what's the difference between a kilowatt and a kilowatt-hour? Devices typically don't run constantly. A kilowatt-hour measures the amount of electricity a device uses during the time it's running. A kilowatt of power consumed by a device over the course of an hour is a kilowatt-hour of energy.

The power rating of a device indicates how long it would take to use a kilowatt-hour. If you have a 100-watt TV, you'd have to binge-watch your favorite shows for 10 hours to use up a kilowatt-hour. However, a 2,000-watt electric stove would burn through a kilowatt-hour in about 30 minutes.

Powering up your kilowatt-hours

You pay for the kilowatt-hours you use. Why not take the time to get more out of your energy dollars? Here are some simple energy-saving tips.

Turn off the lights when you're the last one to leave a room.
Replace conventional incandescent bulbs with LEDs, which use far less energy.
Increase the thermostat temperature when no one is home to reduce air conditioning energy use.
Plug electronic devices into advanced power strips, which automatically cut power to unused devices.
Unplug battery chargers when they're not charging anything.
Wait until you have a full load before running the clothes washer or dishwasher to avoid wasting energy.

Armed with these tips and a better understanding of how you're charged for electricity, you have the power to find ways to save and reduce your energy bills.