Editing Kilowatt-hour (section)

==Unit representations==
A widely used representation of the kilowatt-hour is ''kWh'', derived from its component units, kilowatt and hour. It is commonly used in billing for delivered energy to consumers by [[electric utility]] companies, and in commercial, educational, and scientific publications, and in the media.<ref>[http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=131-11-58 IEC Electropedia, Entry 131-11-58] {{webarchive |url=https://web.archive.org/web/20160314215740/http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=131-11-58 |date=14 March 2016 }}</ref><ref>See for example: [http://www.windpower.org/en/stat/unitsene.htm ''Wind Energy Reference Manual Part 2: Energy and Power Definitions'']  {{webarchive |url= https://web.archive.org/web/20071126132157/http://www.windpower.org/en/stat/unitsene.htm |date=26 November 2007 }} Danish Wind Energy Association. Retrieved 9 January 2008; [http://www.businessdictionary.com/definition/Kilowatt-Hour-kWh.html "Kilowatt-Hour (kWh)"]  {{webarchive|url=https://web.archive.org/web/20160302222956/http://www.businessdictionary.com/definition/Kilowatt-Hour-kWh.html |date=2 March 2016 }} BusinessDictionary.com. Retrieved 9 January 2008; [http://www.world-nuclear.org/info/inf41.html "US Nuclear Power Industry"]  {{webarchive|url=https://web.archive.org/web/20071126132157/http://www.world-nuclear.org/info/inf41.html |date=26 November 2007 }} www.world-nuclear.org. Retrieved 9 January 2008; [http://eeru.open.ac.uk/natta/energy.html#4 "Energy. A Beginners Guide: Making Sense of Units"]  {{webarchive | url= https://web.archive.org/web/20071126132157/http://eeru.open.ac.uk/natta/energy.html |date=26 November 2007 }} ''Renew On Line (UK)''. The [[Open University]]. Retrieved 9 January 2008.</ref> It is also the usual unit representation in electrical power engineering.<ref>ASTM SI10-10, IEEE/ASTM SI 10 American National Standard for Metric Practice, ASTM International, West Conshohocken, PA, 2010, [www.astm.org] "The symbols for certain compound units of electrical power engineering are usually written without separation, thus: watthour (Wh), kilowatthour (kWh), voltampere (VA), and kilovoltampere (kVA)"</ref> This common representation, however, does not comply with the [[style guide]] of the [[International System of Units]] (SI).<ref name="BIPM">{{cite web |title=The International System of Units (SI) |url=https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochure-9-EN.pdf#page=33 |publisher=International Bureau of Weights and Measures (BIPM) |access-date=7 April 2020 |page=147 |date=2019}}</ref>

Other representations of the unit may be encountered:
* ''kW⋅h'' and ''kW&nbsp;h'' are less commonly used, but they are consistent with the SI. The SI brochure<ref name="BIPM" /> states that in forming a compound unit symbol, "Multiplication must be indicated by a space or a [[interpunct|half-high (centred) dot]] (⋅), since otherwise some prefixes could be misinterpreted as a unit symbol." This is supported by a standard<ref>Standard for the Use of the International System of Units (SI): The Modern Metric System. (1997). (IEEE/ASTM SI 10-1997). New York and West Conshohocken, PA: [[Institute of Electrical and Electronics Engineers]] and [[ASTM]]. 15.</ref> issued jointly by an international ([[IEEE]]) and national ([[ASTM]]) organization, and by a major style guide.<ref>{{cite book |title=The Chicago Manual of Style |date=2017 |publisher=University of Chicago Press |location=Chicago |edition=17 |url=https://www.chicagomanualofstyle.org/book/ed17/part2/ch10/psec058.html |access-date=1 April 2020 |chapter=10.57: Units derived from SI base units}}</ref> However, the IEEE/ASTM standard allows ''kWh'' (but does not mention other multiples of the watt-hour). One guide published by [[NIST]] specifically recommends against ''kWh'' "to avoid possible confusion".<ref>{{cite web | url= https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication811e2008.pdf | title= Guide for the Use of the International System of Units (SI) | publisher = [[National Institute of Standards and Technology]] | year= 2008 | quote = Reference [4: ISO 31-0] suggests that if a space is used to indicate units formed by multiplication, the space may be omitted if it does not cause confusion. This possibility is reflected in the common practice of using the symbol kWh rather than kW⋅h or kW&nbsp;h for the kilowatt-hour. Nevertheless, this Guide takes the position that a half-high dot or a space should always be used to avoid possible confusion; | access-date= 6 April 2020}}</ref>
* In 2014, the United States official fuel-economy [[window sticker]] for electric vehicles used the abbreviation ''kW-hrs''.<ref name=fueleconomy>{{cite web|title=Electric Vehicles: Learn More About the New Label |url= http://www.fueleconomy.gov/feg/label/learn-more-electric-label.shtml |website=fueleconomy.gov|publisher=US Department of energy|access-date=10 August 2014}}</ref>
* Variations in capitalization are sometimes encountered: ''KWh'', ''KWH'', ''kwh'', etc., which are inconsistent with the International System of Units.
* The notation ''kW/h'' for the kilowatt-hour is incorrect, as it denotes kilowatt per hour.

The hour is a unit of time listed among the [[Non-SI units mentioned in the SI|non-SI units accepted]] by the [[International Bureau of Weights and Measures]] for use with the SI.<ref name=BIPM /> 

An electric heater consuming 1,000 watts (1 kilowatt) operating for one hour uses one kilowatt-hour of energy. A television consuming 100 watts operating continuously for 10 hours uses one kilowatt-hour. A 40-watt electric appliance operating continuously for 25 hours uses one kilowatt-hour.