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

[hallerb]

it appears in homes that use more water, the typical 2 adults and

2 teenagers savings are less, probably because the standard tank spends more time heating water and less time standing by. this is a new wrinkle on the tank vs tankless discussion

For homes that use 41 gallons or less of hot water daily, demand water heaters can be 24%-34% more energy efficient than conventional storage tank water heaters. They can be 8%-14% more energy efficient for homes that use a lot of hot water--around 86 gallons per day. You can achieve even greater energy savings of 27%-50% if you install a demand water heater at each hot water outlet.

[hallerb]

also note this word of warning

For example, taking a shower and running the dishwasher at the same time can stretch a demand water heater to its limit. To overcome this problem, you can install two or more demand water heaters, connected in parallel for simultaneous demands of hot water. You can also install separate demand water heaters for appliances--such as a clothes washer or dishwater--that use a lot of hot water in your home.

then 2 showers and a dishwasher at same time will require multiple tankless?

it also points out that a tankless with a pilot light can wipe out any savings.....

wonder if the posters here who say their tankless works in a power failure have tankless with pilot light? if so they arent saving anything......

given the tankless high BTU and the flue gas requirements wonder how many could afford multiple tankless around their home????????

[SteveB]

The simple solution: let the kids shower last. Mom and Dad go first and take long long showers to use up all the hot water and let the kids learn that waiting is the result of their taking long showers and being inconsiderate of others. Either that, or they will take colder shorter showers until they catch on. If they ever do.

Steve

[Jeff]

Most dishwashers use the dryer element to further heat up the incoming water anyway. Dishwasher actually use much less water than most people realize.

However making the hot water hotter does mean you use less water from the heated line side in showers and sinks. It will make the difference between occasionally running out of hot water to rarely running out. I set my heater higher than the recommended "mark" on the temp dial specifically to get more shower time out of one tank full of hot water. We have pressure balancing shower valves so there isn't the danger of full hot water in the shower if someone flushes a toilet.

When we had our tank replaced a couple of years ago I had to specifically decline a safety device that would add cold water to the hot water leaving the tank if it detected it was higher than scalding temp. Apparently it is now code for new construction around here. In my mind I can't quite figure out if cooling "very" hot water to "fairly" hot water in the hot water line rather than at the shower fixture would reduce amount of running time for showers from one full tank of hot water. I'm thinking it would act the same as lowering the tank temperature so it would reduce the available run time.

Has anyone installed a hot water recirculator? The theory is that you keep the water in the hot water line hot so that you do not require any run time to get your shower or sink up to temperature.

Jeff

[ransley]

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I have two valves I open with spigots, no taking apart anything to flush.

Look Hallerb Energy Factor is a rating, research it , it was posted here on all tanks made I did not post it, learn to Google and attempt to disprove me, you cant, can you. Learn then post

[ransley]

Only and idiot would want 140-160f, do you have yours to 140? I bet not

[ransley]

Hey Hallerb, here it is, read and learn.

[ransley]

Gee mine was 500 with TAX, what a missinformed negative puts you are.

[hallerb]

te figure

the recurircuate lines saves water but wastes energy unless you turn it on specifically before using a fixture.......

the tempering valves prevent scalds, but keeping a tank hotter increases standby losses, and leads to shorter lank life from the thermal shock of very hot water and very cold water mixing.

there are no free lunches, gain a little here lose a little there.........

i prefer a larger tank, with higher BTU, and a lower temperature so no one can get scalded.........

your mileage may vary......

tankless owners see more wasted water since the tankless must detect flow and turn on burners before hot water arrives

[hallerb]

look all along you have been posting 20% up flue but your own link says.......

", 7% represents the loss through the tank

since stanby helps heat your home in the winter, only 13% is actually lost.

does your tankless have a pilot, if so the government says your saving nothing........ this is highly likely since you stated your tankless works in a power failure

if your home uses a lot of water the standby time is less, and your tankless saves little, according to the government link here

[hallerb]

- Hide quoted text -

you specifically said tankless require no service.......... yet you installed service valves and must clean crud from the heat exchanger.

i buy a new tank, install and forget about it till it leaks in about

10 years, well i may wipe dust off the cover occasionally.......

[ransley]

k.- Hide quoted text -

I have them installed, I never flushed it, it doesnt need it yet, with 9$ total NG bill in summer, including gas dryer and gas stove I know its not limed up yet. BUT IT IS a fact tanks scale, and loose up to 3 % effeciency every year to scale. It is also a fact my Ng bill is

50% more where I am now with a tank, tankless worked for me to cut my bill.

Here is something else to piss you off, tankless are rated for 30 yr life, Tanks are not.

[hallerb]

ank.- Hide quoted text -

show me a 30 year link, longest tankless warranty is 10 years.........

show me a link to 3% a year to scale buildup..........

the last link you posted in my response to your claim 20% went up chimney said 13 % up chimney.

so more links please to prove you dont know whats up

DOES YOUR TANKLESS HAVE A PILOT LIGHT???????

[hallerb]

so how many tankless did you install? you said them............

them is plural..........

but quote 500 bucks, which is suspiciously low.

please post which tankless you installed for 500 bucks each.

[S. Barker]

Yes, i do. Would i make a point out of it if i didn't do it?

s

Only and idiot would want 140-160f, do you have yours to 140? I bet not

[ransley]

uite figure

Thats bull shit in relavance to consumption, mine triggers in 1-2 seconds with maybe 1/2 gallon detection. How about tankless can last

30 years and cut your gas bill in half, Or tankless can have a remote theremostat in your shower so you dont waste money by heating water hotter than you need, which is 102 for me. Or as you say" Tanks heat your home" great idea when AC is running, Or the truth that tanks are really near 60% efficent. Look at a Takagi condensing TK1 its maybe 96% on propane with the SAME energy factor as its efficency rating. Now can you answer why tankless Energy Factor ratings are about the same as the efficency of the burner, because Tanks waste freakin energy up the chimney.

[Wayne Whitney]

Actually, it doesn't say the savings are less, it says the efficiency improvement is less. Standby losses are basically independent of usage. The greater the usage, the smaller the fraction of total costs attributable to standby losses.

So if you are trying to calculate a payback period, and if the incremental efficiency of the tank and tankless are the same, then usage doesn't matter. All you need to do is figure out how much more expensive the tankless is, and how your savings from standby losses are.

Cheers, Wayne

[Wayne Whitney]

No, but it may require a larger, more expensive unit than 1 shower and a dishwasher at the same time. Personally I don't think dishwashers are a big issue, it's no problem to defer dishwasher/clothes washer use until the showering is done.

This shows the article is somewhat out of date. Tankless heaters with pilot lights are pretty old technology.

Cheers, Wayne

[Wayne Whitney]

No, it would act the same as mixing down the "very" hot water at the shower like you do now. It doesn't matter where you do the mixing--by raising the tank temperature you are still increased the amount of heat stored in the tank.

Wayne

[Wayne Whitney]

First, I am the source of the 13% up the chimney number. That is just a rough estimate based on the total 20% standby losses of a gas tank (gas tankless EF 0.80 - gas tank EF 0.60) compared to the 7% standby losses of an efficient electric heater (0.98 EF of an electric tankless - 0.91 EF of an electric tank). The difference is attributable to the flue on a conventional gas tank.

But the 20% standby losses is the more important figure. The losses through the tank periphery are still losses--they can only be considered otherwise if the tank is in conditioned space and you are in a heating-only climate.

No, there's maybe only one model on the market today with a pilot light, out of tens of models.

Wayne