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kW (kilowatt) and kWh (kilowatt-hour) sound very similar, but they’re not. A kilowatt (kW) is a measure of power while a kilowatt-hour (kWh) is a measure of energy.
Understanding the difference between kilowatt and kilowatt-hours can help you save money every month. Planning ahead and recharging home electronics, an electric vehicle, or even running that load of laundry in the evening hours can decrease your kWh consumption.
How can you calculate the saving? What’s the difference between power and energy? Let’s dig in and find some answers and save you a few extra coins every month.
kW vs. kWh : A Side-by-Side Comparison
| Energy (Kilowatt-hours) | Power (Kilowatt) | |
|---|---|---|
| Definition | The capacity to do work | The rate at which energy is transmitted |
| Unit | Joules | Watts |
| Symbol | W | P |
Kilowatt vs. Kilowatt-Hour: What’s the Difference?
Understanding the difference can put cash in your pocket! Let’s break them down below.
Kilowatt (kW) Definition
A kilowatt is a measure of power. Power is the rate at which something (like a coffee pot, dishwasher, countertop oven, electric vehicle charger, or television) uses energy.
Kilowatt-Hour (kWh) Definition
Kilowatt-hours refer to energy, or the capacity to do work. How much energy did you use? We usually run into kWh on our monthly electric bills from the power company.
kW (Kilowatt) vs. kWh (Kilowatt-Hour): Practical Examples
The concepts of kW and kWh are abstract if you’ve not delved into them too much in the past. Let’s decipher the kW and kWh numbers on most of our monthly electric bills.
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Countertop Oven
Let’s assume you love your brand-new countertop oven. You love it so much that you use it several times a day. (Work with us!)
The countertop oven uses 1,300W. You’ll use it twice a day. This allows us to calculate the countertop ovens’ kW and kWh every month.
- 1,300W (countertop oven watts) divided by 1,000 (kilowatts) = 1.3kW
- The countertop oven specifications list 1,300W as the kW
- 1.3kW multiplied by how many hours you’ll use the countertop oven daily.
- 1.3kW x 2 hours= 2.6kW per day
- 2.6kW x 30 days = 78 kWh per month
- The average cost (USA) per kWh is $0.178
- 78 kWh (use) X .178 (cost) = $13.88 per month
- Compact toaster oven that makes meals, snacks, and sides perfectly using a manual temperature control and timer
- Six 1-Touch Controls: Six preset cooking functions for the foods you love, plus reheat, defrost, and more
- Double Infrared Heating
- Removable 9-Inch Inner Baking Tray
- Power: 1,300W
- Dimensions: 12 x 13 x 10.25
- Silver
- Baking rack is connected to the oven door to smoothly pull the rack toward you as the door is opened; auto shut-off helps prevent overcooking and burning
- Compact, attractive design that fits anywhere
Electric Vehicle (EV) Charger
EVs are all the rage, but how much will it cost to charge the tank every night? Let’s calculate it based on the EV charger specifications.
- The EV charger specification doesn’t list the kW, so we calculated it.
- Voltage multiplied by Current equals watts (V x I = W)
- The charger required 240V at 50A = 12,000W
- 12,000W divided by 1,000 = 12kWh
- 12kWh x 2 hours recharge per day = 24kWh per day
- 24kWh per day x 30 days = 720kWh per month
- 720kWh x $0.178 (cost) = $128.16 per month
- Up to 50 Amp
- 240V
- Level 2 Wi-Fi enabled
- UL listed
- Energy star
- NEMA 6-50 plug or hardwired
- Indoor/outdoor
- 23-foot cable
Smart Meters
Utility companies are replacing older electricity consumption meters with intelligent meters. Smart meters allow the power company to monitor consumption in real-time. Increased consumption causes increased power generation. Decreased power consumption results in less power being generated and sent to the electrical grid.
Smart meters allow power companies to predict energy consumption hourly, daily, weekly, and seasonally. Smart meters allow for variable rate utility bills, so gone are the days of a single kWh rate.
Kilowatt vs. Kilowatt-Hour: Your Utility (Power) Bill
Many power companies provide cost incentives to encourage non-peak hours of electrical consumption.
- EV recharging at night: Most EV charger software allows you to configure the charging hours. Plug the EV in when you arrive home, and the charging automatically begins when you tell it to start.
- Washing/drying: Reduced electricity rates aren’t all about eclectic vehicles. Reduced rates are all about shifting energy consumption from peak to non-peak hours.
- The utility company has no idea what you have plugged into your wall outlets that consume power. (Well, that’s not entirely true. A monthly $10,000 bill might raise a few questions.)
- The utility company tracks your total consumption each month.
- All consumption from all outlets during daylight hours = A
- “A” multiplied by peak kW rate
- All consumption from all outlets during nighttime hours = B
- “B” multiplied by non-peak kW rate
- A + B = combined peak and non-peak electricity cost
- All consumption from all outlets during daylight hours = A
kW (Kilowatt) vs. kWh (Kilowatt-Hour): 2 Must-Know Facts
- A Kilowatt (kW) is a measure of power. Power is the rate at which something (like an appliance) uses energy.
- Kilowatt-hours is the energy used to do work. How much energy did you use to operate the Keurig?
kW (Kilowatt) vs. kWh (Kilowatt-Hour): Which One is Better?
A higher kilowatt value (like a space heater) means the appliance will consume more power faster. A lower kilowatt value (like a television) means the application will consume less power at a slower rate.
