Most efficient water heater?

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Basically what we're talking about with the efficiency of water heaters is the percentage of the energy that's put into the system that actually gets applied to the task of heating water. And, of course, a lot depends on where you define the boundary of the system.
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Yes I knew I was wrong the moment I posted it. I was thinking of electric heating and forgot that when heating water some heat would be lost to the room.
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on a tankless feeding a regular tank, it should cost no more to operate than a regular hot water tank.
the tankless initially heats the water to whatever it can, then sends the water to a regular tank that does its normal job.
endless hot water regular tank conveniences and the only extra cost is the line between the tankless and regular tank, ideally it should be short and well insulated.
true the tank will have normal tank losses.
today i have to stop at home depot and while i am there price some hot water tanks. just to verify some of these issues:)
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Maybe not, but is sure costs a lot more in terms of buying and installing 2 water heaters, one of which is tankless and more expensive. With this approach, you incur the higher cost of tankless and by having the second regular tank, you still have the standby losses, which defeat most of the advantage of the tankless that justify it's expense. I fail to see the point. Plenty of folks have a gas tankless for their whole house needs and are happy with it.

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There is no point to this approach, its backwards and will loose you all the savings you just paid for. If the tankless and tank are 82% efficent you are heating with one 82% burner and keeping it warm with another 82% burner. You are heating with the tankless and allowing it to cool in the tank, at about a 20% reduction in efficency rating. Most of what you just paid for in increased efficency goes up the center of the tank and out the chimney. The tank if hooked up should before the tankless and only hold water unheated to allow it to warm up by the surounding air to temper it, it works for me. Even better is to strip of the insulation on the tank, your basement will always be warmer then the incomming water main.
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For pricing a tank look at a cheap uninsulated well tank.
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A much better way to do this is to get an electric tank water heater, remove the heating elements, and wire the thermostat to run a pump on a loop to the tankless heater. Incoming cold and outgoing hot are from the tank iteslf.
This way, the standby losses are that of an electric tank, which is less than a gas tank due to the lack of a flue down the middle. An advantage over tankless only is that the delivered hot water pressure is higher, because the pressure drop from a tank is noticeably less than from a tankless.
When I get around to installing solar hot water, this is probably the way I'm going to go; the solar can be on another loop from the tank.
Cheers, Wayne
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No point to having a tank circulate or change anything as that since you are still talking same burner efficencies, this is dumb.
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On Tue, 18 Mar 2008 07:30:39 -0700 (PDT), ransley wrote:

I should have mentioned that I searched for that PDF during my GAS water heater replacement. http://tinyurl.com/38eh4d
That PDF only contained residential GAS water heater specifications (very many hundreds or even a thousand or more).
It did not have any residential ELECTRIC water heater efficiency ratings (some of which approach 98% due to the fact no heat goes up the flue; it's all absorbed by the water).
Donna
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Don Wiss wrote:

If you're gonna spend lots of money on a water tank you might as well get an oil fired demand water heater. Gives you unlimited hot water and no cost to maintain a tank of hot water. If you want to put a tempering tank in your hot attic save even more.
--
Blattus Slafaly ? 3 :) 7/8

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Uh, where am I going to get oil?
Don <www.donwiss.com> (e-mail link at home page bottom).
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my tankless add on was only for use when familiy is visiting, the remainder of the time my 50 gallon high btu tank is fine.
now 7 people pile in here, and it can become a problem espically when incoming water temperature is 40 degrees
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Its alot of money to put in a tankless and not get the savings year around, first you need to get the supply tested with all other gas apliances running to be sure no upgrade is neded. Do 2 people shower now at the same time, I dont think you will benefit having a tankless before a tank and it will actualy cost more to run since both units burners are probably near in efficency, I put my tankless after my tank with bypass valves incase my old tank leaks, but i havnt used it since installing the tankless, the cheap Bosch.
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its more of a idle thought, the minor standby losses of a regular tank dont bother me, and our tank is plenty big enough, except when family visits. with washing clothes, doing laundry and showering its a busy hot water using place. and our showers have the flow restrictors removed.....
but a new kitchen dining room gut job is a lot more likely and probably better of use of money:) kinda nervous the economy may hurt our income:( and gasoline is killing my service business
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With shower restrictors removed you have to be real carefull, and measure shower output since tankless are real specific on Gpm and the amount of temp rise, [ on the coldest day, when gas pressure is low and everything gas is on, water is 38f incomming] you still need a hot shower. For many a cheap unit would not work, but I guess that really depends on your incomming mains gpm.
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On Sun, 16 Mar 2008 20:27:22 -0400, Don Wiss wrote:

A GUI is available to look up the efficiency of any water heater, residential or commercial at http://www.gamapower.org
For example, residential hot water heater efficiency can be obtained at http://www.gamapower.org/water.php
Or, just call GAMA at 908-464-8200
Donna
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What a poorly designed page! I gave up. Most annoying is each time you return to the page to make a change it clears all your input away and you have to reinput everything.
And it does not seem to include the model GPHE-50 (AO Smith Vertex) that I just had installed.
Don <www.donwiss.com> (e-mail link at home page bottom).
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Smith http://www.gamanet.org/gama/inforesources.nsf/vAttachmentLaunch/BD9C57BA8477D8E185256E9000606CD0 /$FILE/12-07-gas-cwh.pdf
Also: http://www.saskenergy.com/saving_energy/EligibleCondensingWaterHeaters.pdf
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wrote:

Are you sure maybe you just arent searching correctly? When you do a "Run Query" and it comes back with no results DONT hit the back button on your browser. Use the "Modify Query" on the page. It rolls back and there is all your past info you typed. Bubba
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wrote:

But....but.... but.... thats just too easy!! it makes too much sense!!
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