Watt Vs. Kilowatt: What’s the Difference?

How to Convert Watts Into Larger Power Measurements

Luckily, the conversion between watts, kW, MW and GW is fairly simple. You can quickly convert the number of watts (W) to kilowatts (kW) by dividing your wattage by 1,000. 

You can quickly convert kilowatts (kW) to megawatts (MW) by dividing the kilowatts by 1,000.

You guessed it — you can then convert megawatts (MW) to gigawatts (GW) by dividing the megawatts by 1,000. 1,000 MW = 1 GW.

What Is a Kilowatt-Hour (kWh)? 

While watts (W) and kilowatts (kW) are measurements of power, kilowatt-hours (kWh) are units of electrical energy. 

The most important distinction between kW and kWh is that a kilowatt-hour of energy reflects the total amount of electricity used over a period of time. Kilowatts, as we’ve mentioned, refer instead to the rate at which a device can generate or consume electrical power. 

To continue with our hose analogy — kW refers to the potential water pressure of a hose. Kilowatt-hours would measure the amount of water used by a hose over time. The greater the power (or kW), the more water it will use over an hour.

More specifically, a kilowatt-hour measures the energy consumed by a 1,000-watt (W) or 1 kilowatt (kW) electrical appliance operating for one hour. The higher the wattage, the more kWh the appliance has to consume to stay powered over time.  

Here’s a simple example. If you were to keep a 100 W TV turned on for a full hour, it will have consumed 100 watt-hours (Wh), or 0.1 kWh. Let’s look at a few other common appliances and how many kWh of energy they consume over an hour. 

Here’s the equation: (W / 1,000 kW) x 1 hour.

• 100 W lightbulb = 0.1 kWh in an hour
• 1,000 W space heater = 1 kWh in an hour
• 1,500 W dishwasher = 1.5 kWh in an hour
• 2,000 W air conditioner = 2 kWh in an hour

What about 10 hours? The equation would be (W / 1,000 kW) x 10 hours

• 100 W lightbulb = 1 kWh in 10 hours
• 1,000 W space heater = 10 kWh in 10 hours
• 1,500 W dishwasher = 15 kWh in 10 hours
• 2,000 W air conditioner = 20 kWh in 10 hours

Starting to make sense?

Kilowatt-hours (kWh) follow the same conversion patterns as watts and kilowatts. These include: 

• Watt-hours (Wh)
• Megawatt-hours (MWh)
• Gigawatt-hours (GWh) 

Check out this helpful video from Enphase Energy to learn more about kWh and their role in your home energy use.

Why Do Watts (W), Kilowatts (kW) and Kilowatt-Hours (kWh) Matter?

Let’s get down to the dollars and cents — why does it matter? Well, your electricity bill will reflect how many kWh of electricity your home consumed over the month. Your utility company or electricity provider will have a rate that it charges per kWh. 

The average home’s power consumption lands around 881 kWh of electricity per month, depending on the season. If your electricity rate is 17 cents per kWh (about standard), then the average energy bill will land around $139.06 (that’s 889 kWh x $0.17).

If you’re looking to conserve energy, it can be helpful to understand which of your appliances consumes the largest amount of energy. That can help you prioritize which appliances to conserve the use of or to upgrade to energy-efficient models. 

For example, did you know dryers can use up to 5,000 W? Let’s do the math on how much that energy usage would cost you per month if you run your dryer for an hour per day.

5,000 W dryer = 5 kWh in an hour

5 kWh x 30 days = 150 kWh 

150 kWh x $0.17 = $25.50 per month

$25.50 x 12 months = $306 per year

Does $306 a year in energy costs make a big difference in your budget? Then consider investing in a drying rack or energy-efficient dryer. 

Understanding the role of W, kW and kWh is what empowers homeowners to make decisions like these that can reduce their total electricity usage. 

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The cost information presented in this article is derived from a comprehensive analysis, incorporating data from multiple industry sources. The average cost per watt per state was calculated based on figures from Consumer Affairs, Energy Sage, and Berkeley Lab’s Electricity Markets & Policy Department. Additionally, monthly energy consumption and the average monthly cost of electricity were sourced from the U.S. Energy Information Administration, ensuring a well-rounded and accurate representation of the information presented.