The Light Direction Blog:

The Difference Between kW and kWh? by Frank Grobmeier

Understanding the difference between kW and kWh can be confusing, especially if you're not familiar with electrical units of measurement. However, knowing the difference between the two can be incredibly useful, whether you're trying to understand your energy consumption or trying to make sense of your utility bills.

kW stands for kilowatt and is a unit of power, while kWh stands for kilowatt-hour and is a unit of energy. Power is the rate at which energy is used or produced, while energy is the amount of power used or produced over a period of time.

Think of it this way: kW is like the speedometer on a car, measuring how fast the car is moving in a given moment, and kWh is like the odometer, measuring the total distance the car has traveled over time.

kW is often used to measure the power output of an electrical device or system. For example, a laptop charger may have a power rating of 60W or 0.06 kW. This means that the charger is using 0.06 kW of power when it is plugged in and charging your laptop.

On the other hand, kWh is used to measure the amount of energy used over a certain period of time. For example, if you leave a 100W light bulb on for 10 hours, it will use 1 kWh of energy (100W x 10 hours = 1000Wh = 1 kWh). Your utility bill is often measured in kWh, indicating the total energy used over a billing period.

It's important to note that while kW and kWh are related, they are not interchangeable. So to reinforce what we’ve talked about, kW measures the rate of energy consumption, while kWh measures the total amount of energy consumed. To put it another way, kW measures power, while kWh measures energy.

Understanding the difference between these two units can help you make informed decisions about energy usage and better manage your utility bills.

Frank Grobmeier has over 30 years of product management and marketing experience with lighting manufacturers including decades in general lighting and specialty lighting with traditional and LED sources. He currently serves as on the Fanlight / Naturaled marketing management team and resides in the Chicago area.