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What Is A Kilowatt-Hour (kWh)?

Updated: 08/16/2021

A kilowatt-hour is a unit of energy used to measure energy consumption or generation. Electricity providers use kWh to determine how much electricity you consume. If you’ve ever looked at or compared electricity rates, you will see that these rates are priced per kWh.

While that basic explanation may help you understand what you’re looking at on your electric bill, you may also have questions about how they’re calculated, how many you should consume each month and what appliances use the most of them. In this post, we cover all that and more.

Kilowatt-hour (kWh) vs Kilowatts (kW)

To understand the kWh, it’s important to note that kilowatt-hours and kilowatts are not the same. A kilowatt-hour is a unit of energy, while a kilowatt is a unit of power. Here’s how they are connected.

One kilowatt-hour (kWh) equals the amount of energy used if a 1-kilowatt appliance—equal to a 1,000-watt appliance—runs for one hour.

Confused? Let’s use a car analogy to explain the difference between the two:

  • A kW Is The Rate At Which Energy Is Used – You can think of kW as similar to miles per hour (mph), or the speed of a car.
  • A kWh Is The Amount Of Energy Used – You can think of kWh as similar to miles, or the distance traveled by a car.

To put it in perspective using a household appliance, a 700-watt microwave needs electricity at a rate of 700 watts (or .7 kW). Kilowatt-hours tell you how much electricity that microwave used based on how long it was operating. 

Calculating Kilowatt-Hours

Now that you know the relationship between kilowatts and kilowatt-hours, you can understand how kilowatt-hours are calculated. In fact, you can use this information to calculate the electricity consumption of your household appliances. Here’s the formula:

  • Kilowatt-hour consumption = (Appliance Wattage × Hours Used) ÷ 1000

Let’s use this formula in an example. Say you ran that 700-watt microwave from the previous section for two hours straight. How many kilowatt-hours would it consume?

Graphic shows kWh calculation for 700-watt microwave
  • Kilowatt-hour consumption = (Appliance Wattage × Hours Used) ÷ 1000
  • Kilowatt-hour consumption = (700 × 2) ÷ 1000
  • Kilowatt-hour consumption = 1400 ÷ 1000
  • Kilowatt-hour consumption  = 1.4

Using this formula we can see that the 700-watt microwave would consume 1.4 kWh if it ran for two hours.

You can use this formula with any electrical appliance in your home. You just need to know its wattage and how long it was used. 

How Many kWh Does a Typical Home Use?

According to the U.S. Energy Information Administration (EIA), the average home uses about 887 kWh of power monthly, but this can vary significantly based on a variety of factors. Most of these factors revolve around your heating and cooling usage, and your climate: 

  • A/C Usage In Hot Climates – Since air conditioners use a lot of electricity, warmer climates like those in Texas use more kWh to keep their homes cool.
  • Electric Heating In Colder Climates – If you have electric heating in a colder climate like in Connecticut, you can see similar spikes in your electricity consumption in the winter months.
  • The Size Of Your Home – Larger homes need more electricity to keep temperatures comfortable when it is hot or cold outside.
  • The Age Of Your Home –  Older homes tend to have poorer insulation, and in turn, need to consume more energy to heat or cool it.

How Many kWh Do Your Household Appliances Use?

Because appliances have different wattages depending on the specific model, it can be difficult to say exactly how many kWh they consume. However, here are some rough estimates based on one hour of usage and average wattage for basic appliances

  • Central A/C – 3.8 kWh
  • Window A/C – 0.9 kWh
  • Space Heater – 1.5 kWh
  • Water Heater – 4.5 kWh
  • Clothes Washer – 0.8 kWh
  • Clothes Dryer – 3 kWh
  • Oven – 1.2 kWh
  • Dishwasher – 1.2 kWh
  • LCD TV – 0.15 kWh
  • Desktop PC – 0.2 kWh
  • LED Light Bulb – 0.013 kWh

Kilowatt-hour (kWh) FAQs

How much does the a kilowatt-hour cost?

The average residential price per kWh in the US is 13.01¢. However, this can vary significantly based on the state. For example, Louisiana averages 9.8¢ per kWh, while Hawaii averages 32.06¢ per kWh.

How many kWh do I consume each month?

You can find how many kWh you consumed each month by checking your electricity bill. Often, your bill will keep track of how much electricity you have used each month over the past year.

How many kWh should you use per day?

The average home uses around 29.6 kWh a day. However, how much you use depends on a variety of factors, including the size of your home, the types of appliances you use and more.

Why is my kWh consumption high?

There are many reasons why your kWh consumption could be high. First, you should check if your home is properly insulated and ensure your HVAC unit is running properly. Outside of that, you should look into ways that you can cut back on your overall electricity consumption.

How many kWh to charge an electric vehicle?

Kilowatt-hour usage varies depending on the car model, the charging station’s voltage, and the time it takes to charge the vehicle. However, using an average of 4 miles per kWh, an electric vehicle that goes 300 miles per charge would need around 75 kWh to fully charge.