Talk:Water heating

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Chemical and Bio Engineering  
WikiProject icon This article is within the scope of WikiProject Chemical and Bio Engineering, a collaborative effort to improve the coverage of Chemical and Bio Engineering articles on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
 ???  This article has not yet received a rating on the project's quality scale.
 ???  This article has not yet received a rating on the project's importance scale.

Copper Tanks and Type of Heating Element[edit]

The article asserts the following: "The inner tank of the Water heater is the single most important feature of a water heater. The best heaters have a copper container. The second most important feature may be the type of heating element. The cartridge elements score over tubular elements."

Does anyone have any idea why this might be the case? I would assume a copper tank would conduct a lot of heat, and be far less efficient than, say, a plastic tank... ? GBMorris (talk) 13:22, 28 April 2008 (UTC)

T&P Valve Testing[edit]

This statement (below) seems rather biased and contradictory to much of the advice out there, but at the same time does provide a useful tidbit of information. I'm not sure how it should be rephrased though, perhaps something like "Some claim that..."?

"The T&P (Temperature and Pressure) relief valve should not be tested, as it may not stop leaking if you pop it open." —Preceding unsigned comment added by (talk) 13:10, 25 February 2008 (UTC)

I have expanded on this section and removed the assertion that the T&P should not be tested, if it continues to leak after testing, it just shows it's faulty or clogged (letting it run may fix it, by clearing mineral deposits etc from it)

Suggesting *NOT* testing/easing the valve contradicts all the manufacturers and safety authority bulletins I've read on the subject. Bad idea. PeterSmithee (talk) 23:42, 9 December 2008 (UTC)

There is a conundrum here. Years of experience showed me that testing most residential T & P valves is a mistake because the valves are cheaply constructed and fail to reseal as a result of testing; two problems may occur: either 1) The test handle often bends or collapses without opening the valve. These failure-prone operating handles are usually made from light gauge formed aluminum; 2) The valve opens and leaks after closing because of poor/inadequate quality rubber used in the valve seal disk. The rubber usually has hardened due to age and chlorine exposure. This valve seal disk is usually crimped in place and is not repairable in the field, the test now necessitating the complete replacement of the T & P valve. At the same time, the instructions supplied with most T & P valves and water heaters recommend a test from as often as monthly to annually, advice that no doubt originates in the manufacturer's legal department. Commercial grade T & P valves, especially models that are ASME National Board certified, use long life rubber compounds, like Viton, and are easily field replaceable. Unfortunately, valves of the commercial grade sell for about 10 times the price of residential grade valve of the same pipe size. Jpcallan (talk) 00:44, 17 May 2012 (UTC)

Thank you for your information about testing T&P valves. A WP:RS must be found before adding it to the article, but at least some of us appreciate sharing your knowledge here. --Reify-tech (talk) 02:14, 17 May 2012 (UTC)

T&P Valve[edit]

T&P Valve - does it ever need replacement?

If it breaks, yes. Carcharoth 07:06, 17 August 2006 (UTC)

Yes indeed it does if it will not stop leaking and pressure and temperature of water are shown to be within limits, or water will not flow from it. Also if it fails to flow when it should. They should be considered a consumable and are relatively inexpensive. PeterSmithee (talk) 23:40, 9 December 2008 (UTC)

Tankless more efficient?[edit]

The topic of tankless efficiency came up, I did some numbers:

I have a 130L tank. It is heated to 50C. The water comes in at 15C and needs 19MJ to fill. It is wrapped in R3 insulation with a surface area of 1.5m so it loses 0.5W per delta deg C. Thus it loses 17W of heat when hot. That's 13 days worth of storage equivalent to 1 heating cycle.

Where do people get the efficiency claim from? Tankless water heater manufacturers? --njh 00:07, 15 March 2006 (UTC)

R-3 is about 2.5W m^-2 K^-1, so your tank will be losing 1.5*2.5*(50 - 18) = 120W, not 17W. This maps to 2 days, not 13. So if you use 1 tank/day, then over 2 days you heat three tanks, efficiency is about 70% of a tankless solution. As you use less water, tankless systems become even "more efficient". As you use more water, efficiency equalizes, but then a tank becomes increasingly pointless... mdf 14:58, 14 July 2006 (UTC)

Sorry, but R-3 is by definition 3 m^2 K / W, or 0,33 W m^-2 K^-1. GBMorris (talk) 13:30, 28 April 2008 (UTC)

For US residents, tankless is sometimes less efficient. Centralized tankless may result in more water use due to it taking longer for the water to get hot. It may also result in more water use due to the greater availability of endless hot water. In any event, tankless in the US often costs more for the heater and more for the installation. They are more complex and less common, and so cost more to maintain. So even if there were an advantage in efficiency or cost, it might not be enough to ever get "paid back" over the life of the installation. Most support for tankless seems to come from those who make and sell them, and people who think the idea sounds great. But researching actual experiences of users reveals many problems. (R-3 sounds like a very minimal level of insulation for a tank.) 16:23, 16 November 2006 (UTC)

Tankless is either more or less efficient, and this is decided on physical principles, not where one lives. Money, logistics, the consequences of a failure, and the like are important, but unreleated matters re: thermal efficiency (the subject of this section). mdf 21:28, 24 November 2006 (UTC)
And of course, people who make and sell water tanks are selfless dedicates who would never consider, even briefly, promoting their schemes for merely pecuniary purposes. mdf 21:28, 24 November 2006 (UTC)

R-6 seems to be the least tank insulation common in the US. 13:56, 17 November 2006 (UTC)

Going from R-3 to R-6 goes from 2 days to 4 days in the above example, and you've hit ~80% of a tankless's thermal efficiency (everything else held the same). To hit 90%, we need to go to R-12. I've always wondered why just about everything made in North America -- houses, cars, water tanks, etc -- are woefully inefficient. Why not just wrap the tanks in R-20 or more insulation and be done with it? Ah, the Mysteries of the Market ... mdf 21:28, 24 November 2006 (UTC)
R3 is an absurdly low estimate. Most tanked NG/LP water heaters are R-8, and tanked electric water heaters are R-16 to R-25. Due to the low standby losses for tanked electric water heaters, and seeing as how tankless units clog up with scale and lose their efficiency, the benefits of tankless (for those who are currently using tanked electric water heaters) are greatly exaggerated. Moving from tanked NG to tankless NG would also give uninspiring savings. The only tankless conversions that make sense are tanked P -> tankless P, or tanked E/tanked P -> tankless NG. SolarCoordinates (talk) 09:49, 27 June 2011 (UTC)

Anyone reading this might benefit from R-value (insulation): R(SI)= 5.68 R(US); so a US R-25 value is about the same as an "international" R-4.4 value; if you want to use the formula R=T/Q with T in °C (or K) and Q in Watt (per m²), then you have to use the R(SI) value, not the R(US) one. Ssscienccce (talk) 18:12, 6 September 2013 (UTC)

Did you mean R(SI)= R(US)/5.68 ? — Preceding unsigned comment added by (talk) 19:27, 1 October 2013 (UTC)

Anode rod?[edit]

Should the article mention the sacrificial anode rod?

Yes. Also unions, fill and drain valves, sedimentation and periodic flushing (tank-type), costs, typical lives, etc. Keep writing!  :-) 14:24, 25 October 2006 (UTC)

Getting the anode rod out in a typical old installation in a utility closet, without breaking something, can be very hard! We need some good advice. 02:12, 18 November 2006 (UTC)

Wikipedia isn't a how-to site. You can find DIY and repair advice at other sites with your favorite search engine. —QuicksilverT @ 22:59, 16 December 2006 (UTC)

Other Tank-less Considerations

Another thought to issues surrounding Tank-less water heaters;

Much more mechanically/electrically complex than tanked storage units.

Requires electrical power to operate (thermal switches & sensors, gas firing system) - this might be a critical issue in areas were utilities are disrupted by winter or stormy weather. Gas lines are buried and service levels have historically fared better than traditionally strung electric.


Since this is something that does vary a lot around the world, it would be great to have lots of photos, showing typical installations in many different countries. 02:09, 18 November 2006 (UTC)

Tankless Water Heater Info[edit]

This website has made a video and has a couple of guides about water heaters. --Masterplumbersocal 16:36, 11 January 2007 (UTC)

Here are venting instructions for Tankless Water Heaters —Preceding unsigned comment added by (talk) 03:36, 27 September 2007 (UTC)

You sure seem to like

[1] [2] [3] [4]

[5][6] this peson has shared the same interest in that site also (talk · contribs · deleted contribs · edit filter log · WHOIS · RDNS · RBLs · http · block user · block log)

may want to take a look here. What Wikipedia is not, External links policy--Hu12 17:05, 11 January 2007 (UTC)

Do electric tankless water heaters remove floride?

I don't know what 'floride' is, unless that is conspiracy theory speak for 'flouride'... (talk)

Seriously... Is a citation REALLY necessary for the remark about the reduced chance for water damage while using a tankless system? I think common sense is a valid citation here. Hey... I am no longer storing a 50 gallon tank of water in my house. Do you think that decreases my risk of having 50 gallons of water being distributed to the floor if something breaks? (talk) —Preceding undated comment added 11:36, 23 August 2010 (UTC).

I would argue that this advantage should be removed completely - a failure of either a storage or tankless water heater can result in a large amount of water released due to the pressure in the pipes, at least until someone can shut off the water supply. And a 50 gallon tank breaking != all 50 gallons of water stored spilled. (talk) 17:39, 23 August 2010 (UTC)

Tankless Water Heater Image[edit]

Rinnai water heaters.jpg

I have uploaded a file of two commercial tankless water heaters working in parallel. If anyone sees a need for this image, please include in the article.

Image Description: Two Rannai brand, tankless water heaters in a commercial setting. Each unit is rated 199,000 BTU and the two work in parallel, heating water to 185 degrees Fahrenheit. Located on a dairy farm and provide hot water for cleaning milking equipment. --Behrat (talk) 03:48, 18 April 2011 (UTC)

Region-neutral terminaology[edit]

I've made a start on trying to make the article region-neutral since it was (and mostly remains) very US-centric in terminology. I hope I'm not just biasing it in the direction of a UK-centric terminology.

I suggest the term instantaneous may be a good neutral substitute for tankless, and storage for tank-type.

Is the abbreviation DHW OK for hot potable water in domestic uses? I know this is UK usage but does it make sense left of the pond? Any better shorthand to distinguish it from water heated for space heating (which is in a closed system and usually contains chemical additives to prevent corrosion)?

--John Stumbles 22:45, 9 February 2007 (UTC)

I concur, I noticed some other region-centric stuff: In the section "Thermodynamics and economics", it talks about a 40-gallon tank. Almost everywhere in the world uses litres, so why talk about gallons? A 150 litre tank seems awfully small, can this really be typical? And then raising the temperature to 41°C. Why 41? Is that really the temperature of hot water tanks in the US? Here in Australia, the regulations require 60°C to prevent Legionaires disease, and 300Litre tanks are common, twice the size of the example. —Preceding unsigned comment added by (talk) 21:06, 27 January 2011 (UTC)

5 years later and the article is still written around US practices. I'm not sure it even makes sense to have a generalised global article on such a broad subject. Separate articles such as Water heating in North America, Water heating in Europe, Water heating in Australasia etc might be a better way to go. --Ef80 (talk) 22:17, 15 January 2016 (UTC)

Split up article?[edit]

This article goes into a lot of US-specific detail e.g. installation practice which I think does not belong in this article. (I'm not sure where it should go - is Wikipedia the place for it? In the UK we have a wiki offshoot of the news:uk.d-i-y newsgroup where this level of detail would go.)

--John Stumbles 22:46, 9 February 2007 (UTC) what is Closed plumbing

History expansion request[edit]

It would be interesting to have a section on the history of hot water heaters. -- Beland 03:52, 11 April 2007 (UTC)

I second that. Chendy (talk) 14:36, 2 February 2008 (UTC)


What the hell is DHW? Can we have less jargon for us non-experts please. 00:19, 1 May 2007 (UTC)

It is defined in the second paragraph. It probably wouldn't hurt to define it again later in the article. It is acceptable usage in the US and apparently also in the UK. --VMS Mosaic 00:24, 1 May 2007 (UTC)

Done --John Stumbles

Tankless Water Heater Wattage Specifications?[edit]

I was hoping this article would specify the actual wattage range of tankless water heaters. I had to research it on my own and as near as I can tell, for household heaters the Stiebel Eltron [Tempra 36] is the highest at 36kW. [7] The only other device I imagine could ever draw that much power from a household would be a fast charging electric vehicle. I was considering putting info in the article, but I'm not certain how to go about it, and I have no idea what industrial use tankless heaters use. (Maybe in excess of 100kW?) Could someone please edit the tankless heater portion to specify the wattage range?


Could someone with the knowledge add a History section to this (like when DHW appeared, perhaps older systems)? That's what I was primarily looking for in this article. Hrcolyer (talk) 15:52, 7 August 2008 (UTC)

Venting Gas Water Heaters[edit]

What is the difference between conventinally vented vs. direct vented vs. power vented? How does the choice of venting impact installation cost for new systems vs. retrofit / replace? Does the venting strategy or length of venting have an effect on the efficiency of the system? —Preceding unsigned comment added by (talk) 20:57, 3 November 2008 (UTC)

Power venting is generally for the more high-efficiency models, they also require modification to existing installations (often a separate horizontal PVC vent/air supply combo) as they put out much less waste heat, and there is more condensation in the exhaust, hence the horizontal vent. They will also not run without power.PeterSmithee (talk) 23:46, 9 December 2008 (UTC)

Consistency in Units of measure[edit]

It would be nice to see Units sticking to SI. The article changes from degrees C to degrees F, BTU to kW, gallons and gph - US or Imperial - who knows? Very little of the information makes sense without converting at least something to another unit of measure. —Preceding unsigned comment added by (talk) 23:10, 4 March 2009 (UTC)

I think both metric and non-metric measurements are useful, but more consistency is definitely needed. Jodi.a.schneider (talk) 12:37, 13 November 2009 (UTC)


I edit the site to indicate a revision or definition of the vessel/containers used to store hot water, the use of the word tank, while not unusual, hardly defines the complex vessel/container used to store hot water. Hot water heater vessels are in fact process containers that while heating water are also pressurized, a little more complex than just calling it a tank. Best regards...Tankman —Preceding unsigned comment added by (talk) 17:38, 30 July 2009 (UTC)


I think the article should refer to the economics of using a 24/7 water heater. I guess this may sound strange to people living in "cool countries", where a water heater (assuming a non-tankless design) is usually always on (and heating is regulated by some thermostat). But does it always make economical sense to keep water hot at all times, even late at night or during day-time when nobody is at home? Would it not make sense to let the water cool down when not used, assuming the reheating wait time is acceptable? Odedee (talk) 00:22, 31 July 2009 (UTC)

In Denmark (equipped with district heating most places) you usually lower the thermostat set point (from normally say 54C to 45C) at night (e.g. 23:00 to 5:00) in order to lower the heat losses. But it is not normal to turn it completely off. Savings are usually limited, as piping and vessels are well insulated. Note that district heating consumption has no idle consumption (as e.g. gas heaters). --Claus Hindsgaul (talk) 08:24, 31 July 2009 (UTC)

That may be, but in Israel it is universally accepted to keep water heating off unless someone expects to require hot water shortly. Most Israeli homes use solar water heating, so (usually) electric water heaters are off throughout Summer, and are used only in winter. Even then, it is on an as-needed basis, not 24/7 (meaning if someone plans on taking a shower, they would turn on the heater a half hour earlier). I am curious whether this practice is based on good economics, or not. Odedee (talk) 09:36, 31 July 2009 (UTC)


Can a modified image of

Active Solar Water Heater Diagram.svg

be added; where the the solar panel is cut off and where it is stated that the 2 pipes connect to a external (passive) source; eg a ground, water solar or air source; eg via heat pump, deep surface water (see also:

Heat pump system.jpg

) or solar panel (see image above)

Also, add section about deep source water cooling (actually deep source air cooling as it cools air, but water cooling is used to refer to the cooling by water which is confusing).


A few suggestions before it is included:

  • There is no need to specify floors. It is no problem e.g. to place the heat tank in the basement.
  • The hot output from the heat tank should be drawn from the top of the tank. Water near the bottom is cold.

See e.g. the very similar drawing in: [8] --Claus Hindsgaul (talk) 12:41, 18 August 2009 (UTC)

Re the need to specify floors: actually it is beneficial to place the hot water tank just below the roof since it then reduces the piping required to the solar panel. It also reduces simplifies the image.
Re the hot water output, it is already clear that the cold water is at the bottom, as for the single hot water pipe that doesn't begin at the top; this line is drawn in a simplified manner; else the lines would cross —Preceding unsigned comment added by (talk) 13:55, 10 April 2010 (UTC)

NPOV & organization[edit]

One section begins "Tankless water heaters [...] are also available and gaining in popularity," while the much longer "Disadvantages" section (~1000 (!) vs. ~500 words) seems to imply, by relative length, that disadvantages far outweigh advantages. Either this is false, or the popularity is due to some other fact not mentioned in the article. The latter is unlikely.

The "Disadvantages" section is inflated by POV or inaccurate statements such as, "[...]electricity. This makes it impossible to include other heat sources, including renewable energy," (renewable electricity generation is common), as well as multiple items items that are essentially the same (more rapid changes in flow temperature for tankless heaters). Second-person language ("you") is also used inappropriately.

Editors should condense the latter section. PaulKishimoto (talk) 17:20, 8 November 2009 (UTC)

Hot water heater ?[edit]

The phrase "hot water heater" is in the article several times. It is grammatically incorrect, and a incorrect term for water heaters. Why heat hot water? The term should be replaced with "water heater" and a note saying they are often erroneously referred to as "Hot water heaters"--T1980 (talk) 00:31, 12 January 2010 (UTC)

It is the common term used in the US (and perhaps elsewhere), therefore it is by definition not incorrect or erroneous (at least in regard to the US). VMS Mosaic (talk) 04:25, 12 January 2010 (UTC)
Common usage does not make it correct. Remember that the audience of this site is not just the US. —Preceding unsigned comment added by (talk) 20:32, 11 March 2010 (UTC)
A simple Google search shows that "water heater" is more common than "hot water heater"[9][10], so I changed it. I also changed "Volume storage hot water heater", because its few occurrences are only this article and copies of it. — Sebastian 23:10, 12 March 2010 (UTC)
For the record, there was no consensus for any change. VMS Mosaic (talk) 03:58, 13 March 2010 (UTC)
Wikipedia is based on facts, not on personal opinions of individual editors. One editor preferred HWH, but nothing was provided to back up that preference. — Sebastian 02:17, 15 March 2010 (UTC)
The fact is that "hot water heater" is the proper/correct/accurate term in some countries. It has absolutely nothing to do with opinion. In the US a "water heater" would be anything that heats water above ambient temperature (e.g. pet bowel heaters, water trough heaters, aquarium heaters, chemical bath heaters, etc.), whereas a "hot water heater" is a "water heater" which heats water to a temperature which is considered "hot". VMS Mosaic (talk) 04:50, 15 March 2010 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I noticed that you blindly reverted my last edit. I say "blindly" because it was just a click on the "revert" button without any reviewing (see below). Seeing this sort of blind edit warring makes me sad, because it is what drives away many sensible, good-willing editors.

I have no personal bias for or against either term. I only got involved in this when I read the above discussion, saw that there was no reply to the IP editor's statement, did a little bit of research, and concluded that it confirmed that statement. I tried to represent both sides by adding "hot water heaters" to the introduction of the term. (I now realize that it would have been better to add that to the next paragraph. By reviewing, instead of blindly reverting, you could have caught that error and actually improved the article.)

You write "The fact is ...", which is surprising, since you seem to be an experienced editor. As you must know, facts are not established by writing "The fact is ...", but by Wikipedia's standards of reliable sources. Editors' personal interpretations or opinions do not belong here. Your post above is a notch better than a personal opinion, because you provide a plausible explanation, but it is still original research. If you want to establish your preferred term throughout this article, you need to provide a verifiable, authoritative source that it is indeed the only one in worldwide use. If you can not do so, please undo your revert. — Sebastian 21:16, 15 March 2010 (UTC)

Please get your "facts" straight. I most definitely did not do a one button revert. I would never misuse the rollback feature in that way, and I resent the fault accusation that I did.
Actually, I have been less than totally correct; the correct technical term in the US is "domestic hot water heater". Please see [11], [12] and from the United States federal government [13] for non-original research. Whether it is in use worldwide is beside the point. If you (sorry, but you, not me is the one who wants the change) can modify the article in a way which is not pointedly biased against US usage, then I wouldn't have as much of a problem, but I do have a problem with changes which are blatantly biased (for whatever reason) against the US.
And no, I will not undo my undo, but I am open to the argument that the article may use UK centric terms and therefore all terms should be UK centric (which might be a valid argument related to WP:ENGVAR), however I have not analyzed the article in that regard. VMS Mosaic (talk) 04:00, 16 March 2010 (UTC)
OK, this is better. At least we're on the right track now, with actual reliable references. And I agree that the term "domestic hot water heater" is often heard in the US.
I am not so much concerned about WP:ENGVAR, as about whether this article represents a worldwide view of the subject. I therefore wish to encourage those editors from areas that do use the term "water heater", to weigh in with references that demonstrate the use of that term. Please be not discouraged, we do have clear criteria that everyone can follow, and if you feel you're not experienced enough then I will be happy to help you with that.
VMS Mosaic, your discussion of whether you pressed one or two buttons is completely beside the point. The point is that you did so blindly, not taking the time to actually review what you were changing. That, combined with repeated "it's a fact because I say so" arguments, is the hallmark of an edit warrior, and it is what raised my attention. You have improved the latter, and I hope you can improve the former, too. — Sebastian 05:29, 16 March 2010 (UTC)
I did not blindly revert it. I looked at each change in the diff, however after reviewing it again to see if I missed something, there is one quoted term specifically regarding the UK which should have been left alone. I will fix it.
As far as my use of the word "fact", I saw it as much of a fact that "hot water heater" is the term used in the US as it is a fact that "color" is spelled "colour" in the UK. Apparently it is okay to claim that the term "water heater" is factual without proof?
In any case, I am done here. I will not undo or complain if you make your change again. Life (at least mine) is far to short to waste more time on this. My original plan was to leave your edit alone (note that my first comment on it was only "for the record" in case someone else had a problem with the change in the future). VMS Mosaic (talk) 03:40, 17 March 2010 (UTC)
Hmm, I see what you mean. It is interesting that both of us would have been OK with the other's edit, if only the other had communicated better. My reply "Wikipedia is based on facts, not on personal opinions of individual editors" did indeed not meet the standards of nonviolent communication, and I understand that it contributed to this escalation. This serves as a reminder that NVC is a skill we forget, if we don't exercise it continuously. Thank you for reminding me of that. — Sebastian 05:53, 17 March 2010 (UTC)
I had not read that before (thank you). While I'm not sure it applies to all human conflict, I do believe it explains much as to why there was a problem here. I am sorry if I escalated the issue without good reason (I would have been a very great deal better off if I had left well enough alone (my blood pressure was 183/109 right after my previous post which is extremely unhealthy even through I take three blood pressure medications)). That's one reason why I initially was going to look the other way, but I let my ego get in involved. The truth is that an American reading the article would most probably automatically translate "water heater" to "hot water heater". VMS Mosaic (talk) 10:49, 17 March 2010 (UTC)

Pare down this article?[edit]

This article is rife with repetitions; and it has been marked as largely unsourced for almost a year now. I am tempted to pare down this article to about one third its size. Are there any objections? — Sebastian 23:14, 12 March 2010 (UTC)


This article does not touch on the purpose of a deflector within the hot water cylinder design.

For an example of a deflector see: [page 10]

Maybe it is there to improve efficiency by avoiding new high pressure cold water directly contacting the thermostat or maybe it prevents pressursised cold water flow disturbing the stable thermal layer within the cylinder - this is all pure speculation on my part so far and I cannot find a reference to explain it anywhere. —Preceding unsigned comment added by (talk) 22:39, 19 October 2010 (UTC)

Disaster / Emergency Preparedness Considerations[edit]

One thing that you should consider when deciding upon the type of water heater is whether you live in an area that has a tendency towards various emergency situations that result in your electrical power being out for extended periods of time (e.g. hurricanes, winter storms, etc). With electrically heated tank type water heaters, if your electrical power is out for a prolonged period of time, you will find that the water will cool off and you will be having cold showers fairly soon. With a gas heated tank type water heater, it will continue to work just fine without electricity. With the electrically heated tankless water heaters, if you are taking a shower and the electricity goes off, you are very quickly going to be taking a cold shower. During hurricanes, the natural gas supply to homes is a lot more likely to remain than the electrical supply, so even you you are without electricity for weeks, you are still very likely to have a natural gas supply. Even during Katrina with all the flooding, the houses still had natural gas supply (since periodically you would see videos on TV of natural gas bubbling up through the water and on fire). One other problem with tankless natural gas water heaters is that they still require electricity in order to either provide ignition of the gas or to turn the gas control valve on. As such, this might also be a concern during periods when your electricity is off. As far as I've been able to determine, the only water heater that seems to handle most disaster situations is the tank type natural gas heated one.

This is my experience after having gone a week without electricity after Hurricane Ike. Thanks to the fact that my cooktop and water heater were natural gas powered, I was able to run the rest of my house (minus the central air-conditioner) on a 7.5Kw generator backfeeding the electrical system for the house with only minor inconveniences (i.e. needing a window air-conditioner for cooling the sleeping area of the house). The 7.5Kw generator was enough to run the refrigerator, freezer, computers, lights, and everything else in the house since cooking and hot water usage was natural gas powered.

This comment is probably not up to the Wiki standards, but perhaps someone can take this information and massage it into an appropriate section for the article. Grumman581 (talk) 08:01, 27 June 2011 (UTC)

It has been suggested that Hot water storage tank or section be merged into Water heating. Proposed since September 2011[edit]

I disagree that Hot water storage tank should be merged into Water heating. Water heating is already to big (e.g. see Talk:Water_heating#Pare_down_this_article.3F). --Glenn (talk) 08:49, 2 October 2011 (UTC)

Water heating perhaps needs some editing. --Wtshymanski (talk) 14:44, 20 October 2011 (UTC)

I also oppose such a merger. This water heating article is really about Domestic Hot Water (DHW), while the Hot water storage tank article is more focused on heat storage and building heating. Combining the articles will result in a mammoth, confusing article. In the meantime, I've cleaned up this article considerably, though further work is still needed. --Reify-tech (talk) 02:28, 17 May 2012 (UTC)

External link to a calculator[edit]

This is my first time using talk. Someone removed my link to a water heater calculator. I don't understand why. There was a dead link on here for a calculator 2 months ago. It was here for 5 years. I built a much better one and now it is removed. Seoplannow (talk) 14:44, 20 June 2013 (UTC)

Thanks for attempting to contribute the link.
Calculators can be a difficult question. WP is an encyclopedia, so it is interested in information rather than apps that calculate. WP does not have a goal of being a how-to guide about installing hot water heaters or burglar alarms, so some practical information about those topics may not be relevant. There's a difference about somebody reading about water heaters in general and somebody who is looking for advice about replacing his current water heater. WP really doesn't address the latter issue.
The calculator does not supply significant information content. If it were an article that discussed factors that affect hot water usage (rather than being a selecting "teenage girls" needs another 5 gallons of capacity), then it would be more appropriate for this article. As it stands, it's a relatively opaque oracle. Glrx (talk) 18:39, 21 June 2013 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just modified 2 external links on Water heating. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

Question? Archived sources still need to be checked

Cheers.—cyberbot IITalk to my owner:Online 08:10, 2 April 2016 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just modified one external link on Water heating. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit User:Cyberpower678/FaQs#InternetArchiveBot*this simple FaQ for additional information. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

Question? Archived sources still need to be checked

Cheers.—cyberbot IITalk to my owner:Online 01:41, 7 June 2016 (UTC)