kW vs kWh: What's the difference?

Hi Everyone, this is Min and I will introduce the difference between kW and kWh.

These serve two very different purposes and understanding the difference can help you better monitor your electricity bill in the future.

 

 

kW and kWh are units of electrical measurement that are often confused with each other. However, they are quite different.

• kW (kilowatt) is a unit of power. It measures the rate at which energy is used or produced. 
  • For example, a 1,000-watt light bulb uses 1 kW of power.
• kWh (kilowatt-hour) is a unit of energy. It measures the total amount of energy used over a period of time.
  • For example, a 1,000-watt light bulb left on for one hour will use 1 kWh of energy.

In other words, kW tells you how fast something uses energy, while kWh tells you how much energy has been used.

 

 

Here is a table summarizing the difference between kW and kWh:

 

Unit                                                         Definition

 

kW	Kilowatt
kWh	Kilowatt-hour
What it measures	Power
What it tells you	How fast something is using energy
What it tells you	How much energy has been used in total

 

Here are some examples of how kW and kWh are used in real life:

• The power rating of a household appliance is typically given in kW. 
  • For example, a toaster might have a power rating of 1 kW.
• The energy consumption of a household is typically given in kWh. 
  • For example, a household might consume 1,000 kWh of energy monthly.
• The output of a power plant is typically given in kW or MW (megawatts). 
  • For example, a power plant might have an output of 1,000 MW.

Lastly, I will give an example for easy understanding below.

 

Let’s use a 1500W dishwasher you use for two hours per day as an example for calculating kW and kWh on a monthly basis:

1. Divide the wattage by 1,000 to calculate kW: 1500 watts 1,000 = 1.5 kW
2. Multiply the kilowatts by the hours of daily use: 1.5 kW X 2 hours = 3 kWh per day
3. Find the total energy usage for a month (30 days): 3 kWh X 30 days = 90 kWh per month

 

Now that we know the monthly kWh for this device, let’s estimate the energy costs.

Multiply the kWh by your electricity provider’s monthly electricity rates.

For the sake of this example, we’ll say it’s $.07 per kWh:

   90 kWh X $.07 per kWh = $6.30 per month

 

In 2022, the average U.S. household used 911 kWh of electricity per month, according to the U.S. Energy Information Administration (EIA).

 This equates to approximately 25 kWh of power per day.

 

This is the end of this posting and please let me know if you have any comments or questions on this item