Talk:Kilowatt-hour/Archive 1

Archive 1

B.O.T.U.

The B.O.T.U. is an alias ... for the kWh or the Wh?

kWh --Ali@gwc.org.uk 20:18, 4 October 2005 (UTC)

The attempted demise of the KWh

In Australia, all our energy bills are now in joules (and their SI multiples).

While this does allow comparison between gas and electricity prices (for example), it also makes the electricity bill less intelligible to many. Many people would know the cost in KWh of having an electric radiator running overnight, or even of leaving a 60W light globe running 24/7, but wouldn't even try to calculate these costs in joules. Is this an example of disempowerment (no pun intended)? Food for thought? Andrewa 18:55, 19 October 2005 (UTC)

It's an example of why decimal time would be a good idea! If there were 100 seconds in a minute and 100 minutes in an hour and ten hours in a day then conversion between watt-hours and joules would be simple power-of-ten multiplication/division. :-) --Ali@gwc.org.uk 12:23, 1 November 2005 (UTC)

kWh/yr - seconds, hours and years

I just put back the bit about kWh/yr using three units of time in one unit. It was removed with the argument that it wouldn't be interresting info, but I think this discussion at the ref desk proves that some explanation is needed. It is a very confusing unit, so it needs a good explanation. As long as it doesn't have an article of its own (which it doesn't require) the explanation should be here. There are already several links to the section from mentions of kWh/yr in other articles. And I have inroduced the term here only recently, so there needs to be a section for it on Wikipedia. I'm just not sure whether that should be here or under watt. DirkvdM 19:09, 3 August 2006 (UTC)

Milli?

Milli-, kilo-, mega-, giga-, and tera- are the most-used prefixes.

How is milli- a commonly-used prefix? When is milliwatt-hour ever used? That would be the energy used by, e.g., a 100 watt bulb in .036 seconds! I'm taking the milli- out of that list Nik42 06:18, 25 August 2006 (UTC)

cal/kcal

Why are cal and Calorie equivalent in the conversion table? Isn't a Calorie (capital C) a kcal and not just a (lower case c) calorie? —The preceding unsigned comment was added by 168.150.253.56 (talk) 01:09, 8 May 2007 (UTC).

The confusion probably arises from the Food energy uses of these terms. In the case of foods, diets, etc. 1 Calorie = 1,000 calories = 1 kcal. However, as used correctly in this article, calorie is capitalised merely because it's used in the top row as a heading Suckindiesel 20:51, 8 May 2007 (UTC)

Identities

A 60 W light bulb consumes 60 W of power. This is the same as 60 J/s or 216,000 J/h or 60 W·s per second or 60 W·h per hour.

This makes no sense. 24.94.17.47 04:55, 22 Mar 2005 (UTC)

What is the problem?--Patrick 09:24, 22 Mar 2005 (UTC)

I think it can confound certain readers and could be stated in simpler ways. AppleJuggler 05:10, 5 June 2007 (UTC)

seconds and hours

Perhaps instead of writing "1W times 3600s." in the very beginning you could clarify that you mean an hour. Suppose you have a 100w output, then, according to that part of the post, you multiply 100 times 3600 which is not the case according to what is written bellow, i.e. for a 100w bulb you do 0.1kW times 10hours...This is misleading. — Preceding unsigned comment added by 98.198.0.102 (talk) 03:07, 19 July 2007

Citiations Needed

Hey, this page needs citations! It doesn't have any! —Preceding unsigned comment added by 216.206.44.10 (talk) 19:52, 7 September 2007 (UTC)

Watt-hour??

Okay, so I consider myself a clever guy, but I am simply baffled...

Could someone explain exactly what a watt-hour is? I understand its w*h and all that good stuff, but its so confusing.

as stated, "a one-watt load (e.g., light bulb) drawing power for one hour"; how does it differ than a number of watts per hour? How can something be defined as power-time? Thanks! --Pbroks13 (talk) 03:38, 7 December 2007 (UTC)

The units should be chosen so that when used in an equation, the mathematical operations will work equally well on the numbers and the units. For example, if we use the equation

E = P·T

where E is energy in watt hours*, P is power in watts, and T is time in hours, we see that the units watts and hours are being multiplied.

The phrase "watts per hour" impies that watts are being divided by hours. This would be appropriate if power was increasing, such a the power needed to air condition a building increases during the morning, as the day gets hotter. Perhaps for a certain building on a certain day, the air conditioning power increased 2000 watts per hour, from zero watts at 8 AM to 10,000 watts at 1 PM.

Note that the watt, being a unit of power, is formed by dividing joules by seconds; a watt is a joule per second. --Gerry Ashton (talk) 20:02, 9 January 2008 (UTC)

Reasons for the request for help?

Without claiming myself as any kind of expert, what kind of help is needed in here? I noticed that the article got a bit repeating about the non-SI:ness (what a word there) of the unit, but the best I can figure out is comparison between other articles about non-SI units, and a comparison between another energy unit. Maybe that would reveal some directions where to develop this article. Santtus 17:23, 12 December 2005 (UTC)

As a physicist, this page looks fine to me as is. Perhaps engineers would like to add more content? I am going to remove the request for expert help. If someone would like to put it back, they should say why here. Strait 18:04, 12 February 2006 (UTC)

I think this article is quite redundant with the intro section. There's really only about 3 sentences of content before everything is repeated. In the definition section, it repeats the intro, and is also quite redundate. This article could use a wikipedia cleanup. —Preceding unsigned comment added by Ice Ardor (talk • contribs) 23:47, 15 January 2008 (UTC)

Requested move

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was PAGE MOVED per discussion below. -GTBacchus^(talk) 05:35, 25 January 2008 (UTC)

---

Nobody uses the unit watt-hour. It's too small a unit for any practical use. In all scientific work the unit Joule would be used instead. This article should be renamed kilowatt hour. It's a little bit like kilocalorie for food energy, which is normally abbreviated to calorie, although kilowatt hour always retains the kilo- prefix. 199.125.109.135 (talk) 05:19, 18 January 2008 (UTC)

• Support. Neither unit is SI, as of course the SI unit of time is the second, not the hour. Agree that almost nobody uses the watt-hour, while the kilowatt-hour is very widely used. And most of the article is already about the kWh. What refers to the watt-hour is mainly about multiples, and should be reworded to refer to the kWh instead. (But not a close parallel to the calorie IMO, which is a real mess, but fortunately not SI either!) Andrewa (talk) 01:16, 21 January 2008 (UTC)
• Support. Nomination makes sense to me. WHATaintNOcountryIeverHEARDofDOtheySPEAKenglishINwhat (talk) 05:00, 25 January 2008 (UTC)

Discussion

The really observant will notice that I'm using a common, non-SI abbreviation kWh above. This is quite deliberate; I've often thought it a bit bizarre that some pedants insist on following SI conventions for abbreviations that aren't part of the SI system anyway! Andrewa (talk) 00:05, 22 January 2008 (UTC)

The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Revision by Unfree

User:Unfree made a revision, but I reverted it for a number of reasons.

• I know of no source that suggests omitting the space between kilowatt hour. Also, the presence of the footnote implies Taylor supports this usage, but he does not.

• Although the explaination of the relationship to the SI energy unit may be overly long, it shouldn't be omitted altogether.

• The word "exerting" is more often used with force rather than power. --Gerry Ashton (talk) 00:44, 28 February 2008 (UTC)

approximate price in United States

I've never paid an electric bill yet, but about how much does a kWh cost?

It depends on where you are. Some info:

8.94 cents/KWh, US avg, Mar 2005; 18.06 (max) Hawaii, 6.08 (min) Idaho.[1]

7.21 cents/kWh, US avg, 2002; 4.26 (min) Kentucky, 13.39 (max) Hawaii.[2]

20 cents/kWh, California, summer 2001.

8.3 cents/kWh, US avg, Jan 1998; family avg 800 kWh/month, $66.40.[3] Shawnc 15:42, 18 February 2006 (UTC)

And in Manitoba, my April electricity bill works out to 6.246 cents Canadian per kwh, all taxes included. The tail block rate for domestic use over 175 kwh/month is 5.780 cents Canadian per kwh. This may be the lowest or 2nd lowest household electrical rate in North America. --Wtshymanski 23:38, 31 July 2006 (UTC)

what is multipliang factor —Preceding unsigned comment added by 59.161.8.136 (talk) 14:10, August 24, 2007 (UTC)

10.7 cents/kwh average in the thumb and south eastern part of Michigan [4] -- 98.250.40.234 (talk) 18:53, 17 September 2009 (UTC)

Project request

IM DOING A PROJECT, CAN SOMEONE HELP ME! —Preceding unsigned comment added by 72.10.102.3 (talk • contribs) 21:09, 10 December 2009 UT --Jc3s5h (talk) 21:52, 10 December 2009 (UTC)

Could you be more specific? --Jc3s5h (talk) 21:53, 10 December 2009 (UTC)

Requested move 2

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: No move. Ucucha 13:17, 13 February 2010 (UTC)

---

Kilowatt hour → Watt-hour (or Watt hour, see below) — There is a (very) brief discussion above where it was decided to move from "watt-hour" to "kilowatt-hour", apparently based on the use common name principle. I think that was an understandable mistake in this case simply because the standard unit prefix "kilo-" is only that, a prefix. There is such a thing as a "nanowatt-hour", "centiwatt-hour", "gigawatt-hour", etc... so simply picking one prefix (which, admittedly, is the most widely used) it a bit strange. There is some precedent in that the SI system has standardized on "Kilometer" instead of the meter, but they've made a specific exception in that case based on the needs of the SI system. All other units rely on their non-prefixed name (eg.: liter, gram, joule, pascal, etc...), so I don't see any obvious reason that the watt-hour should be different.
— V = I * R (Talk • Contribs) 21:09, 5 February 2010 (UTC)

You mean "kilogram" not "kilometer"... ― A._di_M. (formerly Army1987) 18:17, 7 February 2010 (UTC)

• I agree but could you explain the hyphen? username 1 (talk) 21:37, 5 February 2010 (UTC)

  Sure! Supposedly you're supposed to hyphenate adjectives (but not nouns), so... This lightbulb uses 0.06 kilowatt-hours of electricity every hour it is turned on. but: I just paid for 600 kilowatt hours, today. (I think that's correct, anyway). I guess that we should probably use Watt hour for the article title though, since we're supposed to use nouns for article titles, but using the hyphenated form is such a habit that I didn't really think about it before you asked.
  — V = I * R (Talk • Contribs) 23:37, 5 February 2010 (UTC)

  They are both nouns in that sentence. FWIW, Wikipedia:MOSNUM#Unit_names allows both in these cases (second bullet). ― A._di_M. (formerly Army1987) 18:21, 7 February 2010 (UTC)

• I also agree that the article should focus on watt hour first, as I tried to convey in a previous edit HERE, and that it should then highlight the various multiples with specific discussion when warranted. While kilowatt hour is perhaps more used by the general population for obvious reasons, the base unit is certainly not without use or uncommon, and discussing other multiples as the article does, is logistically awkward when starting with the kW. Kbrose (talk) 22:12, 5 February 2010 (UTC)

The standard unit of energy is the joule, or watt second. I am not convinced that anyone ever uses the watt hour for energy. I suspect energy in that range would instead be measured in kilojoules. In the case of the kilowatt hour, kilo is more than just a prefix, is part of an idiosyncratic non-SI unit of measure. --Jc3s5h (talk) 23:00, 5 February 2010 (UTC)

Please stay on the topic. This article does not concern itself with the question of what the 'standard' unit of energy is, it discusses a common unit of energy used primarily in the electronics and electric utility field. No electronics technician (for example) measures in J, and in this context what you may perceive as 'idiosyncratic' is irrelevant. Kbrose (talk) 23:32, 5 February 2010 (UTC)

I think the comment "it discusses a common unit of energy used primarily in the electronics and electric utility field" shows that the kW⋅h is a unit confined to a particular trade, just like "cord" is confined to the trade that sells firewood. As such, not only is it not an SI unit, but it goes against the entire concept of SI being a universal system of measurements for all purposes. This is on topic, because the idea that you would have an article about the unprefixed unit, and presume that readers could add whatever prefix might be appropriate, is a concept that applies to SI units. The kW⋅h does not necessarily fit that pattern. Jc3s5h (talk) 19:37, 7 February 2010 (UTC)

No, this is incorrect. This has nothing to do with being an SI unit, per se. SI prefixes are used even with non-SI unit and have the identical functionality and rules of application. However, the fact is that the unit watt is an SI unit, only the hour is not, but is accepted for use with SI units. But all of this is not relevant to the proposal. The question that needs to be answered to decide on this move request is, whether the article should reflect the base unit, i.e. the unit without multiples applied, or whether the kilowatt hour has sufficient status of being the primary topic for this group of units, that the article should be named accordingly. In actually use, it is appears clear that the kilowatt hour is NOT the only used size, and it is certainly permissible to use any of the SI prefixes with the watt hour. Why are you suggesting that it isn't? What has this to do with the purpose of SI being a universal system of measurement? Are you suggesting to delete the article, because it's not the SI-standard unit of energy? Kbrose (talk) 20:25, 7 February 2010 (UTC)

I would not delete an article just because it was about a non-SI unit. If we did that we would have to delete acre, foot, yard and many others. It's true that some other metric prefixes are used in practice, but only larger prefixes. Watt hour and milliwatt hour are nearly unheard of.

That is wrong. I have added referenced occurrences to the article. Many SI units aren't used much or at all in certain sizes, that didn't motivate anyone to name the unit articles according to the most used multiple. Kbrose (talk) 21:23, 7 February 2010 (UTC)

Well, the hour might not be a SI unit, but it is a unit approved for use with the SI (or whatever that category was called), FWIW. ― A._di_M. (formerly Army1987) 10:45, 8 February 2010 (UTC)

• Oppose kWh is a standard measure for home electricity billing, and is not an SI unit (it uses hours, not seconds). 70.29.210.242 (talk) 05:50, 6 February 2010 (UTC)

Both statements given here as reasons for objection to the move request have very little (first statement) and nothing (second statement) to do with the question of whether the article should be named kilowatt hours or watt hours. Kbrose (talk) 20:25, 7 February 2010 (UTC)

Oppose on the grounds of common sense; but of course that's not Wikipedia policy. Have fun, fellas....--Wtshymanski (talk) 01:59, 8 February 2010 (UTC)

• Oppose --JWB (talk) 02:51, 8 February 2010 (UTC)
• Weak oppose. Normally I'd say the article should be at the base (i.e., unsuffixed or "kilogram") unit, but this does seem to be one of those rare cases where a multiple is much more common (compare decibel). OTOH the watt-hour is nowhere as rare as the bel, so this case is more borderline. ― A._di_M. (formerly Army1987) 10:45, 8 February 2010 (UTC)
  • Prefix, not suffix. You've got to admire the logical layout of the SI system, where none of the base units have prefixes (except kilogram), and the unit of length is one-ten-millionth of the distance from the equator through the (North) pole through Paris (except when it's the distance between two scratches on a bar, except when it's so many wavelengths of colored light, except when it's the distance light travels in an arbitrary fraction of a second), and the liter is the volume of a 10 cm cube, (except when it's the volume of a kilogram of water). Yes, very logical, indeed. (let's not talk about the ab-, stat- and practical electromagnetic units, please!) --Wtshymanski (talk) 03:05, 12 February 2010 (UTC)
• Oppose. Use common names works fine here. This is not an official SI unit and Wikipedia has other articles about non-base units (e.g., kilometres per hour, centimetre of water, Kilogram-force per square centimetre). — AjaxSmack 03:03, 10 February 2010 (UTC)

  I'm not really convinced but, fair enough. At least we've had a discussion about it now.
  — V = I * R (Talk • Contribs) 01:35, 12 February 2010 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Convenience of kWh vs Joule

The article states that the kWh "is a convenient unit because the energy usage of a typical home in one month is several hundred kilowatt-hours." Why is that more convenient than the Joule? A few hundred kWh is about 1000 MJ or 1 GJ, which seems just as convenient to me, with the added advantage that it's an SI unit. Or do I misunderstand what is meant here? If so, it could do with a rewrite. DirkvdM 09:40, 31 July 2006 (UTC)

SI units aren't necessarily convenient units. Witness your own edits to your comment above! --Wtshymanski 23:34, 31 July 2006 (UTC)

That's not what this is about. I don't make a claim. The article does. I just question that and say that another unit is not less convenient (well actually, it is simply because it's an SI unit, but that's not the point). I don't get your second sentence. What do you mean by that? DirkvdM 12:42, 1 August 2006 (UTC)

Well, for one, it makes for easier calculation. If you havea 100W bulb runing for 1 hr/day, then in a 30-day month it uses 30*1*100 = 3000 watt-hours, or 3 kilowatt-hours. To calculate in joules, you need an additional factor of 3600 10,800,000 joules, or 10.8 megajoules. As long as you know how many watts an appliance uses, it's easy to calculate watt-hours based on hours of usage. Nik42 06:14, 25 August 2006 (UTC)

The Wh is confusing to many non-technical people. People around me seem to understand kWh as kW/h (as in km/h), and sometimes say "kilowatts per hour", thus interpreting it as a rate of something with respect to time. I'm tired of seeing kWh and related magnitudes misused in newspapers and magazines. Using MJ, the numbers would have the same order of magnitude, and there would not be such problems. [asegura] --150.241.250.3 10:40, 31 October 2007 (UTC)

I added a section to the article: "Kilowatts per hour" and a redirect page. Now when you hear that term used you have someplace to redirect them too.Wefoij (talk) 18:22, 24 November 2010 (UTC)

And MJ is better? How many people can even pronounce joule, let alone know what it is. At least light bulbs say "watts" on them so that people can understand that if you turn on a 100 watt light bulb it uses 100 watts, and if you leave it on for 10 hours that's one kilowatt-hour (100x10=1,000). Using MJ to me is a deliberate obfuscation and should be avoided like the plague. 199.125.109.83 (talk) 06:59, 14 May 2008 (UTC)

At the present time, kW∙h is a bit more convenient than joule, because devices that consume in the vicinity of a kW are the ones that have an obvious effect on electric bills. Similarly, when thinking about electric bills, it is more convenient to think in terms of hours than seconds.

In the future, it is possible that the joule might be universally adopted for all energy measurements, such as the energy in food (instead of calories). If this were to happen, education would be enhanced because measuring all energy in the same unit would provide a strong hint to people (including school children) that all these different phenomena are fundamentally the same thing. --Gerry Ashton (talk) 15:42, 14 May 2008 (UTC)

Misused term?

The term kilowatts per hour is often misused by non technical folks. If you don't explicitly use the term, then they may not get it.

Plus if you go changing the titles, it screws up the redirects71.34.87.155 (talk) 15:50, 26 November 2010 (UTC)

True, there's no upper limit to confusion. But I wonder if this is any kinder to people who are that badly confused? --Wtshymanski (talk) 15:58, 26 November 2010 (UTC)

I'm forced to deal with reporters covering energy issues on a regular basis. My goal in trying to get a place that accurately described the fallacy so I could link them to this page. I wasn't worried about kind / unkind. —Preceding unsigned comment added by Wefoij (talk • contribs) 18:14, 26 November 2010 (UTC)

New typo rule for "kWh"

A new RegExTypoFix rule has been set up to change the clearly wrong "KWh", "Kwh", "Kph" → "kWh". I see on this article that there are differences of opinion on the correct abbreviation for kilowatt hour, but a preference towards "kW h" or "kW·h" instead. I've started a discussion on the Typos talk page - you may want to add your thoughts. Thanks! GoingBatty (talk) 05:18, 28 November 2010 (UTC)

Oh great, another robot to clean up after. The bot tenders may want to delete 'Kph' from the things the bot is going to 'fix' since I doubt the bot is clever enough to figure out if the human meant 'kilowatts per hour' or 'kilometers per hour' or something else.--Wtshymanski (talk) 05:38, 28 November 2010 (UTC)

I'm not aware of any bots that use RegExTypoFix. The description makes it clear that the intent is to have a human editor review each edit. GoingBatty (talk) 05:56, 28 November 2010 (UTC)

Confusion of kilowatt hours and kilowatts per hour (simplify tag)

There might be a confusion in come countries utilizing the wrong terminology, or that are culturally rooted with using this term. (probably in the USA)

Yet in order to explain something, one but be quintessential. the explentation is way too long, and actually got me confused, having known this alreay. it needs a revise, preferably to trunc it to a third of it's length. This will produce clarity. Less is More..--Namaste@^? 23:04, 6 December 2010 (UTC)

Note to Ois1974

I moved your comment to the bottom of the page; the convention here is to append newer material there. Also, if you leave a comment on a talk page, "sign" it using four tilde's: ~~~~. That'll put a timestamp in automatically. Thanks! Garamond Lethet
c 03:38, 21 December 2013 (UTC)

I'm sorry, and thanks for reminding me too! :)

==> [Ois1974]

114.79.54.154 (talk) 04:30, 21 December 2013 (UTC)

No worries! Garamond Lethet
c 04:31, 21 December 2013 (UTC)

Multiple Errors in defining (SI) scale/units/symbols

I noticed that many people here simply ignore the fact (thus I had to remind it again many times) that SI has defined "Kilo" as "1000x" of base unit and must be CAPITALIZED (thus MUST USE capital "K" over lowercase "k") to denote it's on the MAJOR/UP scale region (such as Giga[G], Mega[M], Tera[T]) relative to the base reference unit (lowercase letter is used for MINOR/DOWN scale region, such as milli[m], micro[u], pico[p], and so on). So, if you really care about any misuse here, why don't you start from the very basic thing of SI scale unit by writing in capital "K" for Kilo instead of lowercase one, please? (and please help me remind SI guys to re-add the good old degree symbol prefix to Kelvin unit symbol so it wouldn't crash with Kilo symbol that use the same capital "K" (e.g: "°K" vs "K"), or make it lowercase [k] as a quite good alternative to degree prefix/addition [e.g: "k" vs "K"]). Fortunately, there's no "k" symbol predefined in SI Metric on MINOR/DOWN scale region, otherwise you'll mess all the messages you try to deliver to public.

As other alternative for Kelvin symbol (if the old degree prefix is a no go), SI can use more intuitive shorter name form, either: "Kelv", "Klv", "Kvn", "Kn" (recommended for 2-letter symbol, as it has not been defined by SI, AFAIK), "Kv" (lowercase "v", Volt unit uses capital "V", SI norm/standard to honor people used as a unitname by capitalizing it) - examples of an extended over 1-letter symbol just like "Pa" symbol for "Pascal" unit (I've no idea why SI mindlessly sticking to 1-letter symbol for Kelvin that surely conflicts to its own predefined 1-letter scale symbol standard, the "K" symbol for both "Kilo" and "Kelvin" - So, if someone write "1 K" and you don't know the related context/topic (missing context/topic), does it stand for "1 Kelvin" of a temperature unit or "1 Kilo" of a scale unit? Note that, for example, most salaries are written in "K" without monetary/currency unit following it [e.g: I never see "KUSD" symbol for thousands of USD], so SI scale symbols are independent/standalone to other relevant units in actual usages, or the SI scale unit symbols can be use in alone/single form independent to other relevant (base) units as wanted freely).

If you have corrected the "Kilo" scale symbol misuse mistake from using the 'lazy laymen' lowercase one and sweared to use the capital "K" forever from now on just to make firmer of your correct base/foundation of "free-from-misunderstanding" high standard (all terms/things should be consistent from base to the top, right?), then we can move to discuss on issues over the basic unit standard issue, such as the "KWh" symbol misuse people discussing here.

I think "KWh" is another symbol 'marketing' standard used by the power line companies to charge users/subscribers for an hour, instead of 'engineering' one, so "KW.h" definition is not necessary as "KWh" is already a worldwide popular 'unit', thanks to the power line/supply industry writing the "KWh" symbol/'unit' on their meters instead of by specialized respective SI/IEEE/ANSI/etc standard agents (the long-time marketing vs technical terminologies issue), and they thought writing/printing a 'dot' or even a 'floating dot' would make unnecessary higher cost, both to the time/space and money (yes, saving production cost even for just a penny in overall is very precious to them, believe me :-) And you think there's no people could ever possibly 'stingier' than you are?).

So, I think the "KW.h" symbol should stay as an engineering/technical reference only or when discussed in technical groups, and 'dot' as a multiplicative product symbol need not to be floating on the center, most mathics/mathematicians accept standard period symbol as a 'dot' product symbol - please don't make our life even harder by the 'dot' altitude rule since we don't have portable altimeter to measure the altitude of the 'dot' to conform to the proposed 'floating dot' standard. BTW, as also an SI recommended unit for work/power accumulation progress in a time frame, "Joule" unit is not a bad idea, IMHO - that may simplify 'unit symbolization' things and can avoid possible misunderstandings to common people by using non-intuitive/intelligle additive symbols.

People who think "KWh" as "KiloWatt per hour" cannot be blamed either, since they have been getting used to common "mph" (mile/hour, it's an Imperial, not an SI scale-unit of millimeter/hour, which is considered as a microbial pace unit - I see why Americans tend to use lowercase letter for Kilo scale, possibly based on this common writing 'norm' of "mile" symbol and too lazy to see the SI scale standard/definition). It's all about common logics and not exclusive to specific maths (which is correct by all means). If you use an approx. 100-Watt device for an hour and continuously use it for hours, most laymen would say: "the device sucks the power for about 100 W/h", and by language logic this is also correct (averaging the variance in watts sucked for hours, just like averaging your speed/mileage per hour for a trip taken in hours).

It's actually accumulative Watt charge of an hour (it's even too complex to calculate if the devices/wattages used varied in an hour, unless you're a nerd making notes and calcs for that 1 hour total wattage used - that's why the "KWh meter" comes handy to help most non-nerdy laymen to identify the total wattage used in that 1 hour). So, to simplify calculation we use simple constant wattage usage example like this: If you've used 100-Watt device for an hour then you've used 0.1 KWh energy (multiply this to cost per KWh and you'll get the charge you've to pay for that 1 hour usage). If you used that 100-Watt device for 10 hours (100 Watt x 10 hour = 1000 Watt.hour = 1 KW.h) then in total you've used 1 KWh energy for that 10 hours (however, you've to pay just for that 1 KWh usage since the cost is charged based on KWh usage, not the time of usage - you can ignore the 'hours of usage' part, just focus on your "KWh meter" readings). For a basic guidance using common example, if you've used a 1-KW Microwave Oven for less than an hour and nothing else (no other devices except the 1-KW MO) were turned on in that time frame, then you've just to pay for less than "cost per KWh" standard charged by your power line/supply company (and if you use it for exactly an hour continuously then you have to pay the "cost per KWh" times 1 only). I hope these simple common/everyday-use examples can help explain 'alien' things to those confused by the "cost per KWh" calculation out there.

Thank You guys (anyone, including all SI staffs/members - you too have to be responsible to correct this 'Kilo scale symbol' letter case usage mess and somewhat conflicting it with Kelvin symbol to add escalated/upscaled mess even more to public) for your attentions and considerations to this public matter.

==> [2013-12-21 Sat, by Ois1974] 114.79.54.154 (talk) 04:26, 21 December 2013 (UTC)

— Preceding unsigned comment added by 114.79.54.154 (talk • contribs) 03:07, 21 December 2013‎

Moved comment to bottom of page and signed. Garamond Lethet
c 03:38, 21 December 2013 (UTC)

You are incorrect. The prefix 'k' is always lower case. It is the only multiplier prefix that is so. Since there is no submultiplier prefex that starts with 'k' there is no room for confusion as there is with 'm' and 'M' or 'p' and 'P'. As for the rest of what you wrote, please see TLDR. DieSwartzPunkt (talk) 17:14, 13 March 2014 (UTC)

TLDR. But the brief glance I gave to the wall of text revealed another error: watt is a unit of power, Watt was a scientist. Only when the unit is reduced to a symbol, W, is it capitalized. The same pattern is followed with other SI units that are named after people. Jc3s5h (talk) 17:29, 13 March 2014 (UTC)

Fuel Economy sticker

This page [5] is used as a source for this statement: "The US official fuel-economy window sticker for electric vehicles uses the abbreviation 'kW-hrs'". But I'm not seeing that. I'm looking at the fine print, in white on black near the bottom, that starts with "Actual results". The third sentence down sure looks to me like it ends in "kW-hr", not "kW-hrs". So I changed the text in the article to match, but was reverted. The text "kW" does not appear anywhere on that page so I'm assuming it's the image of the sticker that's being used as a source here. Where exactly do you see "kW-hrs" (with an 's')? Kendall-K1 (talk) 15:42, 2 July 2015 (UTC)

The white-on black fine print at the bottom of the page does indeed say "$0.12 per kW-hr"; there is one single kW-hr in that context. Above and to the right of the little car symbol it says "34 kW-hrs per 100 miles". Evidently the authors of the sticker think an "s" should be added to the symbol for the plural. Jc3s5h (talk) 16:26, 2 July 2015 (UTC)

Morons. I guess that's what you get from people who measure energy in "gallon equivalents." Kendall-K1 (talk) 16:36, 2 July 2015 (UTC)

I think the people in NISTs metric program need to be fired (if that hasn't already happened). The fact that they can't even get the federal government to use SI correctly proves they're worthless. Jc3s5h (talk) 18:03, 2 July 2015 (UTC)

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watt-seconds

I just reverted a couple of changes. One of them inserted this: "One watt/second is equal to 1 Joule of energy expended." I think it's a big mistake to write watt·second as "watt/second" because that's too easily confused with "watt per second." Another change was "Physical power can be defined as force available to do work." I don't like that because "force" has a precise meaning; work is force through a distance. I think it's a mistake to use "force" to mean something different. Kendall-K1 (talk) 07:27, 14 February 2016 (UTC)

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Kilowatts per hour

I think the first sentence of the article is incorrect. No (pure number) amount of kwh is equal to any amount of joules. kwh is a unit of power; joules is a unit of energy. Please change the article to reflect this. TheFallibleFiend (talk) 20:04, 11 October 2011 (UTC)== Kilowatts per hour==

No, kW is a unit of power. The hour (h) is a unit of time. When power is expended for a period of time, energy is consumed, so power multiplied by time is energy. Jc3s5h (talk) 20:22, 11 October 2011 (UTC)

You're right, of course. I confused myself trying to do too many things at once. tx, tff TheFallibleFiend (talk) 21:40, 11 October 2011 (UTC)

I would really like to see the practical information needed to figure out how much power an electrical appliance is using. Not all appliances (few anymore) give the wattage, but it can be calculated. I had to go to another site to find out that Watts = Amps * Volts. Since this is article is rated as Start-Class, it really should have basic information in an understandable format. TitaniumMomma (talk) 03:15, 17 July 2012 (UTC) TitaniumMomma

This article isn't about power, it's about energy. Jc3s5h (talk) 13:47, 17 July 2012 (UTC)

Kilowatt per hour (kW/h) is a gradient. Example: If my generator runs at 400 kW, and I increase the power by 100 kW/h then one hour later the output power will be 500 kW. --Gunnar (talk) 13:33, 24 August 2016 (UTC)

kWh

I recently added this abbreviation, which is widely used throughout the world, citing four diverse sources of usage. This edit refers.

This has been reverted by User:Gerry Ashton with the edit summary "Revert incorrect abbreviation. Correct usage of measurements is a matter of law. Unlike other language, popular mistakes do not become correct through popularity."

First of all, I cannot imagine which 'law' applies in every English-speaking country of the world.

Secondly this is not a 'popular mistake' it is simply common usage as the above edit, and thousands of published documents in newspapers and commercial publications will attest to this.

Thirdly, the background to this discussion is an exchange of views at Wikipedia talk:Manual of Style (dates and numbers). Whilst blundering onto this page on another matter it came to my attention that MOS currently specifically requested editors not use the abbreviation - "When units are combined by multiplication, use a middle dot to separate them (kW·h, not kWh, kW h, kW-h, or kW•h)". Given the ubiqiuity of the kWh's use in the world in general I found this surprising and (perhaps unwisely) became in involved in the discussion. After completing the above edit my last word at MOSNUM was "If for practical reasons that still elude me MOSNUM wishes to use a less common style, so be it, but the article [i.e. watt-hour] should reflect international usage, not exclude information to suit MOS."

In other words, given the ubiqiuity of 'kWh' at the very least it would behoove this article to explain why it is an error of some kind to use it (assuming this is genuinely the case) citing appropriate sources rather than attempting to suppress information. (The article itself uses it for goodness sake!)

There may be a lengthy and complex background to this issue I am unaware of. The comments of others are requested. Ben MacDui^Talk/Walk 20:11, 9 January 2008 (UTC)

I would welcome including information in the article explaining that this usage is contrary to the recommendation of a number of national and international measurement authorities. It would be a bit tricky establishing that the error is widespread, because conducting surveys or counting Google hits is generally considered original research.

This usage creates a few problems:

• In algebra, variables consist of a single character (discounting subscripts and superscripts), so writing variables next to each other without a space unambiguously indicates multiplication.
• Symbols may consist of more that one character, so at the very least, the reader will have to mentally sort through the possible valid unit symbols and decide from context where the omitted multiplication symbol(s) should be inserted. In some cases, there may be more than one valid interpretation, so the reader would have to determine from context which best applies to the situation. For example, kWhm^-2 might mean kilowatt hour per square meter, or kilowatt per square hectometer.
• SI is intended to be uniform in all fields, to maximize understanding by those not familiar with the jargon of a particular field. Thus, accepting poor usage because it is commonplace within a field creates a barrier to outsiders who wish to learn about the field. --Gerry Ashton (talk) 20:32, 9 January 2008 (UTC)

I have no difficulty whatever with a note to the effect that although kWh is widely used it is not recommended by a number of national and international measurement authorities, assuming this is verifiable. However…. I can't agree that "that the error is widespread". I rather think it is true that its usage is widely accepted as standard across a variety of nations and fields of endeavour. It is, at least in the UK the usual form in almost all walks of life. SI's intentions are no doubt worthy, and there may, in some circumstances, be reasons to adopt this usage to avoid ambiguity. 'Kilowatt per square hectometer' is not a measurement which is commonly used in the electricity generating industry for example, and no real confusion arises. (I have seen kWh/m for kilowatt hour per square meter). I am not an engineer, but in my experience neither space nor dot is commonly used in popular or commercial literature here. I had a quick look at some UK academic literature - all that I saw used 'kWh'.

SI may well be intended to be uniform in all fields, and one day its aims may be achieved. Nonetheless, we don't all speak Esperanto just because someone thinks it's a good idea.

Any amendment needs to avoid calling widespread and well-understood usage an 'error'.

Perhaps something along the lines of "The abbreviation kWh is also widely used internationally, although the SI system does not recommend this use."<sundry refs>. Ben MacDui^Talk/Walk 19:10, 10 January 2008 (UTC)

I absolutely reject the notion that the correctness of a unit of measure can be determined by widespread usage in publications. Publications only reflect the final result of unpublished calculations. The units used in those unpublished calculations may be quite complex and unusual, and the calculations are error-prone. Using strictly correct units during those calculations helps prevent errors, and facilitate the checking of those calculations by colleagues. If reference publications, such as Wikipedia, promote incorrect usage, it will encourage newcomers to technical fields to make errors in their calculations.

I also notice that while you want to include "kWh", you don't propose to include "Wh".

Finally, I am not aware of any reliable source we can cite that says "kWh" is widely used. --Gerry Ashton (talk) 19:45, 10 January 2008 (UTC)

May I chip in here? It seems to me that there are two legitimate roles for this article that are relevant here. One is to state the correct symbol for the kilowatt hour (or watt hour), which is kW h (or W h); another is to point out that the reader may find other common abbreviations used (eg kWh). It needs to be established that use of kWh is widespread, but if so, then I think it should be mentioned, including an indication of where one might expect to find it (electricity bills?). Thunderbird2 (talk) 20:03, 10 January 2008 (UTC)

Well if you try The Chicago Manual of Style and the American Physical Society for starters. There were the four now deleted refs I provided [6] including the Danish Wind Energy Association, BusinessDictionary.com, www.world-nuclear.org and the UK's Open University. How many more would you like? Ben MacDui^Talk/Walk 20:24, 10 January 2008 (UTC)

Of the sources suggested by Ben MacDui, the Chicago Manual of Style (I have the outdated 14 ed.) shows "kWh" on page 482, grouped with other "units other than SI units". So that is a citable source proving that "kWh" is in widespread use. The American Physical Society web link is not working for me, so I can't comment. The four sources mentioned earlier were just examples of usage by individual publications, so were unpursuasive that the usage was widespread.

I would suggest a mention in the article indicating that the usage is not recommended by a national measurement authority (NIST) nor by an international standard-setting organization (IEEE), and that if the practice of indicating multiplication of unit symbols by writing them with no intervening half-high dot or space were followed in general, ambiguous unit symbols could result. --Gerry Ashton (talk) 21:44, 10 January 2008 (UTC)

I have added a small caveat about kWh's continuing use in variety of publications. If you want more references for it the are of course many tens of thousands available. As I said at MOSNUM I think the case for 'kw h' is being overstated but I lack the inclination to pursue the matter. I wish you good luck in your crusade to rid the world of this useful but apparently offensive little acronym, although I fear you will have a frustrating time of it. Ben MacDui^Talk/Walk 20:41, 11 January 2008 (UTC)

It is kWh without any dots. The same is true for MVA. The dots are an artificial element, not used in real life. --Gunnar (talk) 13:29, 24 August 2016 (UTC)

"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 h for the kilowatt hour." Thompson, Ambler and Taylor, Barry N. (2008). Guide for the Use of the International System of Units (SI) (Special publication 811). Gaithersburg, MD: National Institute of Standards and Technology. p. 12 -> common practise is kWh --Gunnar (talk) 13:41, 24 August 2016 (UTC)

Suggest move to Kilowatt-hour

We should use the hyphenated form (kilowatt-hour, watt-hour, megawatt-hour, etc.) because that's what major dictionaries show. This article now is a hodgepodge of hyphenated and unhyphenated cases. Chris the speller ^yack 16:59, 8 July 2015 (UTC)

This has been discussed before. I'm not willing to dredge it up again unless the proponent provides a summary of, and pointers to, the previous discussions. Jc3s5h (talk) 18:28, 8 July 2015 (UTC)

I don't find any previous discussion of this. I find discussions about whether the title should use the "kilo-" prefix, and in those discussions "kilowatt-hour" is bandied about with and without the hyphen, as if the parties paid no real attention to the hyphen. I am not for dredging up old discussions, but for getting the article to hyphenate "kilowatt-hour" as oxforddictionaries.com, macmillandictionary.com and merriam-webster.com show. Previous discussions do not trump dictionaries. Chris the speller ^yack 19:02, 8 July 2015 (UTC)

OK, NIST Special Publication 881, in section 6.1.5 "Unit symbols obtained by multiplication", uses "kilowatt hour". I think technical publications should overrule general-interest publications for technical articles. Can you show any science or technology dictionaries that use "kilowatt-hour"? Jc3s5h (talk) 19:56, 8 July 2015 (UTC)

I haven't looked into it, but McGraw-Hill Dictionary of Scientific and Technical Terms (1997) uses a hyphen, according to the section #Hyphenates, above. Contrary to my last edit, that section does briefly discuss hyphenation, but does not reach anything like a conclusion. I don't think technical publications should overrule general-interest publications; Wikipedia is for the general public, not just for electrical engineers. If major dictionaries use a hyphen, then that's what the general public will expect, and that's what they should find. Chris the speller ^yack 22:34, 8 July 2015 (UTC)

WP:COMMONNAME says to use the "name most typically used in reliable sources." "This includes usage in the sources used as references for the article." For this article, that's "kilowatt hour" without the hyphen. Kendall-K1 (talk) 02:28, 9 July 2015 (UTC)

The sources used in this article vary. In eia.gov I found "kilowatthour". I'm sure we agree that hyphenation is better than that choice. Businessdictionary.com says "kilowatt-hour". Some sources have "watt-hour" (hyphenated) right alongside "kilowatt hour" (unhyphenated); make sense of that. Most of the sources give the impression that they don't think very hard about hyphenation or lack of it; the dictionaries sure do, and no major dictionary omits the hyphen. Chris the speller ^yack 17:05, 9 July 2015 (UTC)

IEC's Electropedia uses kilowatthour. There are some grammar rules for hyphens. Which apply here? --Gunnar (talk) 14:07, 24 August 2016 (UTC)

uncapitalisation

Heading all the discussion in the article about what is and isn't acceptable as an abbreviation stands the title. The title, as is standard in WP, is capitalised as Kilowatt hour. Given that it is bad form in any of the abbreviations to use a capital 'K', such a large prominent capital K in the title is unfortunate. Should we vary from WP norms in this instance, have a completely lower- case title 'kilowatt hour' for the article, and if need be add a redirect from the capitalised version? Gravuritas (talk) 14:00, 24 August 2016 (UTC)

No, the title is correct. Titles use sentence case. It's capitalised just as it would be at the beginning of a sentence. Kendall-K1 (talk) 15:23, 24 August 2016 (UTC)

Additionally: the Wikipedia software forces capitalisation of the first word of any article title. --Elektrik Fanne 16:46, 4 September 2016 (UTC)

Hyphenates

The protocol I've always followed in expressing "units over time" is to do so with hyphenates, i.e. ampere-hour, watt-hour. And indeed this is how they appear in the McGraw-Hill Dictionary of Scientific and Technical Terms (1997). My electric bills from First Energy Corp. use "Kilowatt-hour (kWh)" as the billable unit.

Shouldn't we follow protocol here and rename the article "Kilowatt-hour" with a redirect from "Kilowatt hour"; and of course add hyphens where appropriate.

This would also make it conform with the article "Electricity meter".

Cheers, Rico402 (talk) 06:44, 3 January 2009 (UTC)

Addendum: I see Barry N. Taylor's Guide for the Use of the International System of Units (SI) (1995) doesn't use hyphenates, so if that's the official stance then I guess I'll yield, but I don't like it, too confusing. Rico402 (talk) 07:01, 3 January 2009 (UTC)

No. We should move it to watt-hour where it belongs. Whatever prefixes are added to it, all those things which redirect here such as megawatt hour and megawatt-hour, fit better with an article which doesn't contain prefixes. There is some justification for having our primary article at kilogram since that prefixed unit is the base unit in the International System of Units, the modern metric system. There is no such justification in this case. Gene Nygaard (talk) 03:30, 23 January 2009 (UTC)

There is a rule in ISO 80000-1:2009 "Quantities and units -- Part 1: General":

7.2.4 English names of compound units

In the English language, the name of the product of two units is the concatenation of the two names, separated by a space.

EXAMPLE 1 newton metre

--Gunnar (talk) 16:53, 23 October 2016 (UTC)

Post-move discussion

The limited discussion discussion above totally fails to take into consideration the simple fact that megawatt-hours, gigawatt-hours, and terawatt-hours are in general use (and common on Wikipedia), and other prefixes also see some use, and redirect to this article, and make more sense if the article is at "watt-hour". It also fails to take into consideration the question of whether or not to use that hyphen. Gene Nygaard (talk) 22:13, 17 February 2008 (UTC)

Megawatt-hours, etc. are not as common though. Everyone gets an electric bill, usually in kilowatt hours, very few people ever hear megawatt-hour, gigawatt-hour etc. 199.125.109.38 (talk) 02:46, 19 March 2008 (UTC)

Megawatt hours are quite common in energy trading. Usually, you get a qoute on the energy exchange which is nominated by the megawatt hour. --Gunnar (talk) 17:53, 26 October 2016 (UTC)

Where does the 114 come from in "One terawatt hour is equal to a sustained power of approximately 114 megawatts for a period of one year."?

It appears in 2 examples:

• "One terawatt hour is equal to a sustained power of approximately 114 megawatts for a period of one year."
• "One kilowatt hour per year equals about 114.08 milliwatts applied constantly during one year."

Thy --SvenAERTS (talk) 16:14, 2 November 2016 (UTC)

There are about 8760 hours in a year. 114 is 1 / 8760 / 1000000. The 1000000 scales from mega to tera, or from milli to kilo. Kendall-K1 (talk) 17:43, 2 November 2016 (UTC)

Discussion concerning kWh and kW(dot)h on WP Manual of Style

Apparently there is a discussion on the use of 'kWh' vs 'kW·h' at Wikipedia talk:Manual of Style/Dates and numbers#Kilowatt-hour. Hallucegenia (talk) 12:05, 4 August 2014 (UTC)

For the record, the consensus was that "kWh" is overwhelmingly used in practice by reliable sources in power engineering, supported by the definition (as 3.6 MJ) by IEEE Std 260.1-2004 of the unit kilowatthour (symbol kWh); and from IEEE/ASTM SI 10-2010: "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)". Unless anyone objects, I shall adjust the article accordingly. Hallucegenia (talk) 18:11, 9 August 2014 (UTC)

That's only half of the story. NIST states: "... in the common practice of using the symbol kWh rather than kW · h or kW 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; for this same reason, only one of these two allowed forms should be used in any given manuscript." --Robertiki (talk) 03:55, 13 March 2017 (UTC)

Derivation of 3.6×10⁶

I've been asked to explain this revert: [7]

The added footnote, to me, implies that 3.6×10⁶ is derived from 1 / 2.77778×10⁻⁴, which is not the case. I could maybe go along with switching it around to something like "= 3.6×10⁶ ≅ 1 / 2.77778×10⁻⁴" but I don't see the point. Kendall-K1 (talk) 22:10, 6 July 2017 (UTC)

The derivation is that a watt is energy expenditure at the rate of one joule per second. A watt hour is the expenditure at a rate of one watt for a period of one hour. There are 3600 seconds in an hour, so 3600 watt seconds are equivalent to 1 watt hour. Or, using the usual method of converting units by multiplying the starting quantity by representations of 1, and cancelling out equal factors in numerators and denominators,

3600 watt seconds × (1 minute / 60 seconds) × (1 hour/ 60 minutes) = 1 watt hour

Jc3s5h (talk) 00:08, 7 July 2017 (UTC)

Agreed. I'm objecting to the insertion of 2.77778×10⁻⁴. Kendall-K1 (talk) 00:19, 7 July 2017 (UTC)

Question on kWh from top

kWh is an abbreviation, right? For kilowatthour or kilowatt-hour?
S.

Webster says kilowatt-hour -- Egil

The characters "kWh" is an incorrect symbol; the correct versions are "kW·h" or "kW h". It is short for "kilowatt hour" or "kilowatt-hour". Standard for Use ofthe International System of Units (SI): The Modern Metric System published by IEEE and ASTM in 1997, on page 14, says that when working with spelled-out unit names, the preferred way to show multiplication is by leaving a space between the units, but a hyphen is also acceptable. --Gerry Ashton (talk) 20:44, 9 January 2008 (UTC)

There's a technical sense in which that is correct, if the term were to be used in scientific papers, which it isn't. In common usage, kWh often occurs. It doesn't matter which it means. Andrewa (talk) 01:20, 21 January 2008 (UTC)

There is no hyphen: "watt hour - non-SI unit of active energy: 1 Wh ≔ 3 600 J

Note 1 to entry: The multiple kilowatt hour, kWh, is commonly used for billing consumers of electric energy and is therefore indicated on electric energy meters." Source IEV, that is the terminology dictionary of the International Electrotechnical Commission --Gunnar (talk) 18:18, 15 July 2017 (UTC)

Watts per hour- delete?

Despite the explanation in the article that includes a legitimate use of a ramp up sequence at a power station in MW/h, I suggest that it should be deleted. The number of times around the world that MW/h or KW/h is used correctly is so tiny relative to the frequency of their misuse that, to a first approximation, we can almost say that all use of these terms is incorrect. Non-technical people reading it are just likely to get confused. Technical people won't look at this page for guidance anyway, as they won't need it. How about just saying- "The use of kilowatts per hour or similar terms is normally a misnomer." Gravuritas (talk) 00:06, 25 September 2013 (UTC)

I've just had another look and think that, by putting "watts per hour" in its own section, the whole thing is clearer, so I've changed it. Having two confusions in one section was confusing. Gravuritas (talk) 09:30, 26 September 2013 (UTC)

I've added a {{cn}}-tag. Despite the one online mention referenced, this seems to me to be an example of schoolkid-illiteracy that occurs in every field. Extolling errors that might occur is not the function of an encyclopaedia, unless occurrence thereof is notable. —Quondum 14:59, 17 July 2017 (UTC)

kW/h

@Quondum: You added a "cn" tag to this statement: "The notation 'kW/h', as a symbol for kilowatt hour, is not correct, as it denotes kilowatt per hour instead." I don't think that's quite the right tag, as I believe we can all agree this statement is true and obvious, right? I think you are actually questioning whether this needs to be said. While I don't have a source I can cite, a quick search turns up many examples of this misuse,[8] and I know I've seen it many times. Kendall-K1 (talk) 15:11, 17 July 2017 (UTC)

Scanning through the examples brought up by the search you give, I see exclusively "answers.com"-type occurrences, with a smattering of crowd-sourced online dictionaries. I don't succeed in getting Google's n-gram viewer to help. {{cn}} might not feel like the correct tag, but I think it is appropriate: unless a notable source can be found supporting the statement, it should be deleted (IMO). To put it another way, if every moderately common source of confusion that occurs exclusively at the high-school level about every subject was noted in WP, we'd burden all readers with considerably more noise about confusions than information about the topic. WP is not there to tutor people to be aware of the misconceptions they might have, but rather to act as a reference for the notable information that they need. I think it is sufficient to have the redirect kw/h pointed at this page. The confusion between kWh and kW, by contrast, seems to be far more notable, just like GDP is almost routinely quoted in dollars, not dollar per annum, and interest is given as a percentage, not a percentage over one year. —Quondum 15:43, 17 July 2017 (UTC)

I disagree. I find this to be one of the most commonly misused unit expressions of any kind, not just among electrical units. Jc3s5h (talk) 16:56, 17 July 2017 (UTC)

I also disagree. The title of the section is "Symbol and abbreviations for kilowatt hour", so commonly used abbreviations which are wrong are part of the scope. --Gunnar (talk) 22:19, 10 August 2017 (UTC)

Here is a source that says "KW/hr" is acceptable: [9] Kendall-K1 (talk) 19:33, 17 July 2017 (UTC)

Heh. And it does not list kW/h, or any of the other variants of kW⋅h mentioned in the article. —Quondum 20:47, 17 July 2017 (UTC)

Email to Elsevier Publishing, Ref.: ISBN 0-444-51241-1 Elsevier's Dictionary of Acronyms, Initialisms, Abbreviations and Symbols

 Dear Quality Assurance Manager,
 In the book cited above you find on page 341:
 1. kW.;kW;kw kilowatt.
 only kW is correct, as k means kilo and W means watt. No dot and no minuscule "kw".
 2. KWh; kW/hr kilowatt-hour.
 Both are incorrect abbreviations. Use a small k for kilo and the "/" means divided by. kW divided by hr is either nonsense or means a power gradient. Correct abbreviation for kilowatt hour is "kWh". BTW, according to ISO 80000-1:2009, Quantities and units -- Part 1: General: "In the English language, the name of the product of two units is the concatenation of the two names, separated by a space." So please erase the dash between kilowatt and hour and use a space instead.

 Please have these errors corrected for the next edition of the abbreviation's dictionary.
 
 Regards, Gunnar Kaestle

"I believe we can all agree this statement is true and obvious, right?" Yes, it is obvious. kW is means kilowatt, h is the hour, / is the division sign. So anyone who didn't sleep through primary school will see the often made mistake "kW/h" are kilowatts per hour (similar to kilometers per hour km/h) which is a speed of power change or a power gradient. This is not original research, this is common sense. I think it is ridiculous to ask a nobel price winner to publish an article on this fact in order to cite that. We can write down simple things without citation if anybody with a basic technical understanding can validate this. --Gunnar (talk) 21:51, 10 August 2017 (UTC)

WP is not a how-to, and we discourage editorializing (telling readers what to do). But I think it would be ok in this case to note that some people use "kW/h" or similar and that it's not correct. Did you get an answer from Elsevier? Kendall-K1 (talk) 22:25, 10 August 2017 (UTC)

Light bulb examples

We should change the light bulb examples. A "40 watt light bulb" typically no longer consumes 40 watts. Which is nonsense of course but I fear it may lead to confusion. Kendall-K1 (talk) 18:56, 4 September 2017 (UTC)

dimensional analysis

Your dimensional analysis leaves people flabbergasted.

Watt=kg.m^2.s^-3 (instantaneous)

Watt.hr= kg.m^2.s^-3.hr

You should put that in, even the executives go dumb with their eyes turning hazzlenut, when they think about multiplying hours out with 3600sec/1hr.

Just to further bother, at 60 hz, you have 60 clock ticks, so you could multiple that in, just to get your accounting corrected.

200.44.94.65 (talk) 14:16, 24 February 2018 (UTC)

Example in intro

Please explain the objection to including a simple example in the intro, which is supposed to summarize the article.--agr (talk) 14:25, 3 July 2018 (UTC)

I can't think of a really simple example. The only device regular folks used to know the power of was the light bulb, but with compact fluorescent or LED light bulbs, the power of an incandescent bulb that yields the same amount of light as the bulb in the package is usually much more prominent on the package than the actual power required. Jc3s5h (talk) 15:58, 3 July 2018 (UTC)

It seems unnecessarily confusing to me. If the consensus is to add an example, let's make it clear that it's an example. The wording I removed sounded like a definition. Kendall-K1 (talk) 16:12, 3 July 2018 (UTC)

In the intro, we could explicitly say "For example, a 100 watt incandescent bulb burning for 10 hours uses one kilowatt hour." People still know what incandescents are, and we could expand on that in the Examples section by pointing out that a 16 watt LED bulb with the same light output as a 100 watt incandescent would burn for over 62 hours on one kilowatt hour of electricity. That would convey the concept better than some of the examples we currently have.--agr (talk) 15:56, 4 July 2018 (UTC)

That strikes me as too complicated for the lead. Maybe if the example were reiterated in a later section, and the part about the LED bulb were explained there. Jc3s5h (talk) 18:25, 4 July 2018 (UTC)

We do have an Examples section. If we want one for the lead, I would go for the first one, which seems simplest and avoids the light bulb problem: "An electric heater rated at 1000 watts (1 kilowatt), operating for one hour uses one kilowatt hour of energy." Kendall-K1 (talk) 22:23, 4 July 2018 (UTC)

I do not see the need for an example in the intro. And a device "rated for 1000 W", is unlikely to use exactly 1 kWh in one hour. We should stay close to the definition. "It is the amount of energy equal to the constant use of 1000 watts during one hour." −Woodstone (talk) 07:36, 5 July 2018 (UTC)

The intro is supposed to summarize the article, not just give a definition. We have a whole section on examples, so including a simple one in the intro is appropriate. I prefer a 100 W, 10 hour example because it make the concept clearer., but i won't quibble.--agr (talk) 21:12, 6 July 2018 (UTC)

Consumption of electric vehicles

Does anyone think the addition of this mostly unsourced section is a good idea? Apparently the editor who added it doesn't care to discuss it. Kendall-K1 (talk) 19:33, 15 August 2018 (UTC)

The consumption of electric vehicles is expressed in kWh/100 km

I don't think this is always true: "The consumption of electric vehicles is expressed in kWh/100 km". For example, the US EPA several different units, including "kW·hrs per 100 miles", but not kWh/100 km, as can be seen on the window sticker. I would suggest changing "is" to "may be". Kendall-K1 (talk) 20:35, 16 August 2018 (UTC)

Sorry for not responding earlier. I just wanted to write that either 1 kWh/100 km or 1 kWh/100 miles contains kWh. It makes sense to mention the consumption of electric vehicles, here. I performed a small calculation for you. 1 kWh/100 km = 36 N or 1 kWh/100 miles = 22.37 N

Here is a European website: [10]. The consumption is given in kWh/100 km, --JeffMik1 (talk) 18:52, 17 August 2018 (UTC)

Where does it say "The rate of energy consumption of electric vehicles is often expressed in kWh/100 km" on that web site? I can't find it. Kendall-K1 (talk) 19:23, 17 August 2018 (UTC)

Here you have :[11] website Spritmonitor. It is interesting, insn't it? --JeffMik1 (talk) 17:18, 20 August 2018 (UTC)

I'm starting to think this may be a case of WP:OR. Kendall-K1 (talk) 17:29, 20 August 2018 (UTC)

It is difficult to convince you that I'm right. Look here, please: Electric car energy efficiency The efficiency is given in kWh/100 km or in kWh100 miles. Do you agree? Thank you, --JeffMik1 (talk) 16:20, 21 August 2018 (UTC)

I'm not interested in your (or my) opinion as to whether you are right. I'm asking for verifiability, which is part of the Wikipedia:Five pillars. Kendall-K1 (talk) 17:28, 21 August 2018 (UTC)

Here is the official site of the United States Department of Energy, which is responsible for energy in the US: [12]. Here, efficiency is given in kWh/100 mile. If you prefer this unit, please replace kWh/100 km through kWh/100 mile (with the conversion factor 1 kWh/100 mile = 1.609344 kWh/100 km). Thanks, but I'm sorry. I give up, --JeffMik1 (talk) 19:32, 21 August 2018 (UTC)