kilowatt-hour
C1Technical/Formal
Definition
Meaning
A unit of electrical energy equivalent to one kilowatt of power used for one hour.
A standard billing unit for electricity consumption, representing the total energy transferred or used.
Linguistics
Semantic Notes
A compound noun that functions as a countable, measurable unit. Often abbreviated as kWh. It represents energy, not power (which is measured in kilowatts).
Dialectal Variation
British vs American Usage
Differences
No difference in meaning or usage. Spelling is consistent as a hyphenated compound.
Connotations
Neutral, technical unit in both varieties.
Frequency
Equally frequent in technical, academic, and utility/billing contexts in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
[Number] kilowatt-hour(s) of electricityconsume/use [number] kilowatt-hour(s)cost/price of [number] kilowatt-hour(s)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “The meter is running (implying kilowatt-hours are accumulating and costing money)”
Usage
Context Usage
Business
Used on utility bills and in energy contracts. 'Our fixed-rate tariff is 25p per kilowatt-hour.'
Academic
Used in physics, engineering, and environmental studies. 'The turbine's annual output was 1.2 million kilowatt-hours.'
Everyday
Used when discussing home electricity usage or bills. 'Our fridge uses about one kilowatt-hour per day.'
Technical
Precise unit in electrical system design, renewable energy capacity, and appliance specifications. 'The battery storage capacity is 13.5 kilowatt-hours.'
Examples
By Part of Speech
verb
British English
- The system is rated to kilowatt-hour the output for billing.
American English
- The software will kilowatt-hour the consumption data.
adjective
British English
- The kilowatt-hour rate has increased this quarter.
American English
- We need the kilowatt-hour usage figures for the report.
Examples
By CEFR Level
- My electricity bill shows how many kilowatt-hours I used.
- A new washing machine can save you many kilowatt-hours each year.
Learning
Memory Aids
Mnemonic
Imagine a KILO of WATT light bulbs running for one HOUR; that's the energy a kilowatt-hour delivers.
Conceptual Metaphor
ENERGY IS A COMMODITY (bought, sold, and measured in discrete units like kilowatt-hours).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid literal translation ('киловатт-час' is correct).
- Do not confuse with 'киловатт' (kilowatt), which is power, not energy.
- In Russian, it is often abbreviated as 'кВт·ч'. Ensure the concept is understood as a measure of total energy used over time, not instantaneous power.
Common Mistakes
- Writing as 'kilowatt/hour' (incorrect, it's multiplicative, not a rate).
- Using plural 'kilowatts-hour' (incorrect; the first element remains singular: 'kilowatt-hours').
- Confusing it with 'kilowatt' (power vs. energy).
Practice
Quiz
What does a kilowatt-hour measure?
FAQ
Frequently Asked Questions
No. 'Kilowatt-hour' is a unit of energy (power multiplied by time). 'Kilowatt per hour' would be a rate of change of power, which is rarely used.
It is almost universally abbreviated as 'kWh'. Note the 'W' is often capitalised in the abbreviation.
Yes. For example, 'The house used 850 kilowatt-hours last month.' The plural is formed by adding an 's' to 'hour'.
Often not. In casual conversation, people might say 'units' on their electricity bill or just 'kWh'. The full term is more common in written or technical contexts.