kilowatt-hour

American  

[kil-uh-wot-ouuhr, -ou-er] / ˈkɪl əˌwɒtˈaʊər, -ˈaʊ ər /

noun

1. a unit of energy, equivalent to the energy transferred or expended in one hour by one kilowatt of power; approximately 1.34 horsepower-hours. kWh, K.W.H., kwhr

---

kilowatt-hour British  

noun

1.  kWh.  a unit of energy equal to the work done by a power of 1000 watts in one hour

---

kilowatt-hour Scientific  

1. A unit used to measure energy, especially electrical energy in commercial applications. One kilowatt-hour is equal to one kilowatt of power produced or consumed over a period of one hour, or 3.6 × 10 ⁶ joules.

---

kilowatt-hour Cultural  

1. A unit of energy: the expenditure of one kilowatt of power for one hour. A toaster running for an hour will use about this much energy.

---

Etymology

Origin of kilowatt-hour

First recorded in 1890–95

Compare meaning

How does kilowatt-hour compare to similar and commonly confused words? Explore the most common comparisons:

• kilowatt vs. kilowatt-hour

Example Sentences

However, when electricity is priced below 20 cents a kilowatt-hour, the systems might not make up their cost in energy savings during their usable lives, he adds.

From The Wall Street Journal • Jun. 5, 2026

But as heat pumps run on electricity, he is now paying around 27p per kilowatt-hour, compared with less than 6p for gas that powers a boiler - more than four times as much.

From BBC • Apr. 15, 2026

The iron-based battery chemistry, called lithium ferrophosphate, or LFP, costs up to 30% less a kilowatt-hour compared with nickel-manganese-cobalt batteries, the type South Korean and Japanese companies usually produce, industry experts say.

From The Wall Street Journal • Mar. 24, 2026

Average U.S. city electricity prices are 19 cents per kilowatt-hour, a 43% increase since late 2019.

From Barron's • Oct. 19, 2025

One kilowatt-hour per sol is ... it can be anything . . . um ...

From "The Martian" by Andy Weir