40 gal just not enough: Replacing water heater for 2400 sq home. Family of 2 adults + 2 children

[trader4]

I don't think that's fair. Ransley says he's actually bought one for $500 and installed it himself relatively easy. And he's happy with the results. I think his opinion is worth more than most here most of whom don't have one and just sling mud. Especially those that continue to spout misleading information, like "The heat loss from a tank unit helps heat your home in the winter." It's been pointed out repeatidly that much of the waste heat in a gas tank unit goes up the flue. And the heat that escapes the sides of the tank only helps heat the house if it happens to be in the living space, which isn't where most are located. And then, in summer, the heat is still added to the house and if you have AC as most do, then you're paying to remove that heat. Yet, this same sad misinformation continues.

[George]

Out of curiosity what residential applications need those high water temperatures?

[RicodJour]

The Bosch units can be dialed up to 140 degrees. I realize that you get more water at a given temperature when you start with hotter water and mix in cold, but what do you need 160 degree water for? Considering that most of the time you'll mix it down to 120 degrees and the anti-scald showers won't let you go anywhere near 160, what's the point of heating water just to cool it down? If your system is undersized for the amount of hot water you need, cranking up the water temperature is a backwards way of adjusting it.

R

[Wayne Whitney]

I don't understand this criticism, we've been over this before. The energy factor of typical gas tankless is 0.80 and the energy factor of a typical gas tank is 0.60. The difference, 20% of the theoretical heat value of the gas used, is the standby losses. Most of the standby losses go up the central flue of a conventional gas tank water heater, as there can't be any insulation between the flue and the hot water.

Yours, Wayne

[Paul M. Eldridge]

The OP has an electric water heater and electric units do not have stack related losses. The only loss is through the tank wall and these losses are less than 1 kWh per day if the tank has an EF of 0.93 or better (the new minimum standard is 0.91).

Secondly, if the tank is located inside a conditioned space any heat loss through the wall *will* offset a portion of the home's space heating demand. If the home is electrically heated the net loss is effectively zero during the heating season and for those who heat with oil, the losses could result in a net positive gain now that residential fuel oil is more expensive than electricity in many parts of the country.

With respect to air conditioning, a central air unit with a SEER of 10 would eliminate 2.94 kWh of heat for every 1.0 kWh consumed (the ratio is 3.8 kWh to 1 for a 13 SEER unit). Thus, the additional a/c burden for a 10 SEER model if tank losses are 0.91 kWh/day would be less than

10 kWh/month.

Cheers, Paul

[S. Barker]

dishwasher.

s

[S. Barker]

a. if you crank them up that high, you'll get no useable flow to speak of b. i'd never have an antiscald shower valve c. the hotter the water is to begin with, the longer it'll last mixed down.

steve

[RicodJour]

No he doesn't. OP wrote: "Ok, our 40 gal gas water heater is failing. About 10 years old, which I hear is ok."

Most of the water heat inefficiency goes up the flue, so do most of the dollars. It's an odd argument to state that putting a heater (waste heat from the water heater) in a location that you don't need it, is a smart move. Maybe we should all go back to the huge ass furnaces under the house with one central floor grate to heat the home. Then none of the inefficiency is lost...unfortunately most of the comfort is.

R

[Thomas G. Marshall]

[e-mail] said something like:

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I don't believe it is an advantage. Are you asking for me to explain? I need not---I agree with the article.

You may have misread both Bill and I.

[RicodJour]

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He seems to be in one of 'those' moods. ;)

Whatever It Is, I'm Against It

I don't know what they have to say, It makes no difference anyway -- Whatever it is, I'm against it! No matter what it is or who commenced it, I'm against it.

Your proposition may be good But let's have one thing understood -- Whatever it is, I'm against it! And even when you've changed it or condensed it, I'm against it.

I'm opposed to it -- On general principles I'm opposed to it!

Chorus: He's opposed to it! In fact, in word, in deed, He's opposed to it!

For months before my son was born, I used to yell from night till morn, Whatever it is, I'm against it! And I've kept yelling since I first commenced it, I'm against it!

By Harry Ruby (music) and Bert Kalmar (lyrics) Performed by Groucho Marx in "Horse Feathers" (1932)

[Matt W. Barrow]

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Or, maybe he's just wrong...

[S. Barker]

now THAT's funny. I don't care who you are. LMMFAO!!

s

[cshenk]

"Thomas G. Marshall" wrote

Should be 15 but if it's hard worked, perhaps 10 is ok.

40G is ok. Not optimal for long showers if there are several and need to take them within 20 mins of each other (night time shower with several kids).

Yup. If you can, go 50/60G. More is overkill.

Yes though it will let all 4 shower within minutes of each other.

Not with a mere 10-20G difference

Has more to do with construction of your place. If it has to fit in a cabinet for example, that cabinet may not be sized safely to hold a larger unit. There may be distance from the walls for example involved.

Sorry, cant answer. If it helps though I have a 40G GE 'Smart Saver' gas hot water heater. I do have to be a bit careful to not take a shower or bath right after running the dishwasher or another's shower. 20 mins seems to work for the wait. It's 14 years old and i seem to recall the wait 10 years ago was about 10 mins so we may be getting near replacement time. IT's in the garage so there is no space problem if we get a bigger one.

[trader4]

Yes, but that has nothing to do with much of the mis-information and slams directed against tankless units. All I'm saying is Ransley actually has one, paid $500 for it, installed it without too much effort and says it works well for him. That's some actual data, instead of speculation.

Also, the vast majority of tankless are not going to be compared to electric water heaters, but instead to gas ones. That's because almost everywhere, it's cheaper to heat water with gas than electric. So, someone looking for a water heater with gas available, isn't going to be looking at electric and then you do have the heat loss via flue.

Yes, that's true, but as I already pointed out:

1 - At least one regular poster here continually mentions the winter benefit of heat loss without regard to where the water heater is located and totally ignores the AC impact in the summer.

2 - Most water heaters are not located in a conditioned space.

3 - In the grand scheme of things, this whole heat loss benefit is a nit.

[hallerb]

most water heaters are in basements, heat rises, so standby losses help heat your home. or in a closet on a living floor, again standby loss heats its suroundings, thats where you live.

again please post a link that says 20% go up the chimney........ please a link....... please........ all i see is someone stating it must be....

since the cost beween a regular tank and a tankless can easily be a grand, that $ could be spent for added insulation and weatherstripping

[Wayne Whitney]

Take a look at , in particular the life-cycle costs comparison. This shows a typical gas tank water heater has an energy factor of 0.60, and a typical gas tankless has an energy factor of 0.80. The difference of 20% represents the standby losses. Prior computations suggest that of those standby losses, 7% represents the loss through the tank insulation, and 13% represents the loss through the gas flue.

Cheers, Wayne

[RicodJour]

Reading what I wrote, I'm wondering what I wrote, and am overwrought by that writing. How wrong my writing was.

I can only assume temporary insanity, or possession by demons.

R

[SteveB]

Been a long long long long time since you've bought or even looked at a water heater, I'd say

[Dioclese]

If the users of said hot water are old enough, yet not too old to move out of the way quickly, just bump the temp setting up higher. Adjustment to less hot water for comfort should save some hot water for other purposes. Extremely lengthy showers are always a concern. They may be longer as a result, with same lack of hot water. The predominant male is in order to fix that lack of discipline.

[glen stark]

Hi everyone.

I'd like to try and elevate the tankless vs. tank discussion a little bit. Let me just say however, kudos for actually bringing a citation into the conversation (WP article). Unfortunately the cited article is severely flawed. It attempts to generalize from anecdotal evidence, and neglects to mention a key benefit of tankless systems: they have an expected life time of OVER 20 YEARS (citation below).

The US department of energy discusses the pros and cons of the system, and I hope we can all agree that they are a reasonably reliable and unbiased source.

Check out:

I recommend reading the whole page. It's brief and highly informative. QUOTED from the DOE website:

-Most tankless water heaters have a life expectancy of more than 20 years. They also have easily replaceable parts that extend their life by many more years. In contrast, storage water heaters last 10?15 years.

-[tankless water heaters] don't produce the standby energy losses associated with storage water heaters, which can save you money.

Whether or not a tankless system is good for your requires a little thought. If you have a problem with instantaneous flow (e.g. you want to be able to run your washer, dishwasher, and have everyone take a shower simultaneously), a tankless system to meet your needs will likely be impractical. Your problem seems to be more length periods of continuous use, which would indicate that you could seriously benefit from a tankless system.

If you really need water > 140F, they probably aren't a good solution for you. The vast majority of homeowners however do not.

If all you care about is the dollars and cents of it, the solution is to get a couple of quotes from reliable contractors, look at your personal energy rates, and do the math. It's pretty easy math, but if you have trouble with it, I'll be glad to help.

If you care about energy conservation, then you can rest assured that you will be doing a good thing for the environment, you won't lose any money in the long run, and you might even profit from it. The latter case seems to be the most likely, in my analysis.

GS