What is a kilowatt-hour?

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Posted on Jul 26 2024 in Energy
Electric meter

BY BRIAN REYNOLDS

One of the keys to understanding the utility industry or your utility bill is understanding the terminology.

A common term is kilowatt-hour, the standard billing unit for electrical energy, abbreviated as kWh.

It is worth noting that a kilowatt is a unit of power, while a kilowatt-hour is a unit of energy. In other words, power is the rate at which energy is consumed or produced, while energy is the quantity of electricity consumed or produced over a certain amount of time. And don’t confuse those two with kilowatt per hour, which would be the rate of change in the flow of power.

One popular analogy is a bucket being filled with water.

The rate at which the water flows into the bucket represents electrical power, aka the kilowatt, while the amount of water in the bucket represents electrical energy, aka the kilowatt-hour.

The higher the rate of flowing water, the quicker the bucket fills up. Likewise, the more power being used or produced, the faster energy is consumed or produced.

With that in mind, the cost of running an electrical device is calculated by multiplying the power consumption in kilowatts by the operating time in hours and then multiplying by the price per kilowatt-hour, which is subject to change. However, the current average price in Indiana is about 15 cents per kilowatt-hour, according to the U.S. Energy Information Administration.

So, how do we put a kilowatt-hour in practical terms?

As far as human power is concerned, a healthy adult performing manual labor performs work equal to about half a kilowatt-hour throughout an eight-hour workday.

Even in that description, note the inclusion of time when a kilowatt-hour is discussed. This is a must.

For example, I can tell you that an air conditioner uses 10 kilowatt-hours, but you would want to know for how long — a day, two days, a week?

The answer is going to make a big difference on your electric bill.

If your air conditioner uses 10 kilowatt-hours per week, you’re paying for approximately 40 kilowatt-hours ($6) per month. But if the air conditioner uses 10 kilowatt-hours per day, you’re paying approximately 280 kilowatt-hours ($42) per month.

The official United States fuel economy window sticker for electric vehicles now uses kilowatt-hours, showing that the more we understand the term, the more we know how it relates to our lives.

Brian Reynolds is the energy advisor at Jackson County REMC in Brownstown, Indiana.