The Difference Between Kilowatts and Kilowatt Hours

Chappell residence

If you’ve ever looked closely at your electric bill, you’ve probably noticed abbreviations like “kWH” and “kW”. You might also have information like “Total kWH” and “Average kWH per day” on your bill. But do you know what those abbreviations and numbers mean?

You may know, or have guessed, that KW refers to kilowatts. KWH is the abbreviation for kilowatt hour. Knowing these terms can help you better understand how you’re being charged for electricity, which appliances use the most energy, and how to lower your bills every month.

Kilowatt vs. Kilowatt Hour

A kilowatt is a measure of power that equals 1,000 watts. 

A kilowatt hour is not how many kilowatts you use per hour, but a measure of the amount of energy you would use if you kept a 1,000 watt appliance running for one hour. 

In other words, think about how long it would take running an appliance to reach a kilowatt (1,000 watts) of use. This entire time, whether it is one hour or 100 hours, is one kWH.

For example, an appliance that uses 500 watts would use 1 kWH in two hours and 100 watt lightbulb would take 10 hours to use 1 kWH. 

Kilowatt hours give you a better idea of your energy consumption than simply looking at the kilowatt usage.

What Are Some Examples of kWH?

Since wattage use differs among brands, it’s difficult to know exactly how much power appliances use without knowing the brand and make. Here are a few estimates based on general household appliances:

  • Baking with a 2,000 watt oven for half an hour
  • Using a 1,000 watt hair dryer for one hour
  • Ironing with a 1,000 watt iron for one hour
  • Using a 500 watt vacuum cleaner for two hours
  • Listening to music on a 100 watt stereo for 10 hours
  • Using a 50 watt laptop for 20 hours
  • Charging your phone with a 20 watt charger for 50 hours

How to Calculate Kilowatt Hours

Calculating the kWH for your appliances is easier than you think! Most appliances have the wattage listed on a label. If you have this information, you can calculate the kWH by dividing the watts on the appliance by 1,000 and multiplying it by the hours used.

Let’s use the 100 watt lightbulb. 1,000 divided by 100 is 10. If we turn that light on for 1 hour, we will have used 10 watts, or .1  kWH. We’d need to leave that light on for 10 hours to use an entire kWH.

Why Measure Energy Usage With kWH?

Understanding kWH can help you better understand how you’re being charged for electricity each month. It can also help you lower your energy costs!

Most electric companies bill by the kilowatt hour. Choosing appliances that consume electricity at a lower rate is one way to lower your monthly energy bills. (Of course, choosing subpar appliances because they consume energy at a lower rate may end up costing the same or more if you have to run them for longer periods of time to get the energy you need.)

Learn How Switching to Solar Can Save You Even More Money!

By adding solar power to your home, you’ll reduce your home’s reliance on the electric company, which reduces the number of kWH you’ll be charged for. To learn more, schedule your free home solar analysis today!

Dan Lezama, the founder and current owner of Sun Dollar Energy, LLC.

Dan Lezama is the founder and current owner of Sun Dollar Energy, LLC. He is a licensed electrician and general contractor with over 14 years of experience in residential solar installation. If you have any further questions about this article, reach out to Sun Dollar Energy at 919.508.6907.