Is this a house being built or an older one ? If older, you will have to
have heavy wiring or a gas line ran. Location may be a factor, If it is
very cold in the area, many of the tankless may not heat the water hot
enough for you.
Cost is usually much more for the tankless.
I would say stay with the tank.
Hi,
When I was considering the tankless, the initial cost was VERY high.
We have 4 bathrooms of which one has a Jacuzzi tub. Installing bigger
gas feed line, preparing to mount the unit on the wall, correct unit
sizing, etc. Felt like I was getting into possible headaches. Stayed
with NG gas fired conventional top end model tanks. At least I could
replace tanks twice and some for the cost of tankless install.
On Thursday, August 8, 2013 2:29:48 PM UTC-4, Kurt Ullman wrote:
If you use a lot of hot water I think the tankless will edge out the tanks. But you need to have the gas or electrical supply. Tankless use a lot of energy over a short period requiring big "pipes" to get it to them
I'm sure there were, but I wasn't there to hear them talking.
I'm told it was something like this
Tankless: Hey, you need to lose some water weight.
Tank: Why would I listen to you? You have no substance.
.
Christopher A. Young
Learn about Jesus
www.lds.org
.
On 8/8/2013 2:29 PM, Kurt Ullman wrote:
If it were me, I would stick with the conventional tank style water
heaters because they CAN supply all the hot water you need, whereas
that's still a big question with tankless heaters.
In fact, in a house in the town I grew up in, the builder (who was a
plumber by trade) put a ball valve in the basement separating the
kitchen and one bathroom from the laundry room and the other bathroom.
He installed two 60 gallon hot water tanks and had one to supply each
side of the house. He did that because he had three daughters and they
were always fighting over the one bathroom in their old house.
I thought that was actually a smart idea because the cost of a water
heater isn't that much, AND the two water heaters don't have to be
identical. They can be totally different and his system would still
work fine. And, the best part of it is, if you ever have to shut one
water heater down (to replace the annode rod, for example), then you can
open that ball valve and have the heater that's still operational
supply water to the whole house until the work is done.
If I were building a house, that's probably the route I'd go.
On Thursday, August 8, 2013 8:30:15 PM UTC-4, nestork wrote:
No reason it's a big question. You determine your maximum simultaneous
demand, the lowest incoming water temp, and buy a tankless that is
spec'd to deliver it. They all have that spec, it's not a mystery.
So, there is a similar sizing problem with the tank type.
The downside of course is that you have to replace two water heaters
when they reach EOL.
Maybe, but there's little difference in economy.
The lifespan of a water heater's tank is largely determined by the
amount of thermal shocking it endures, and that's directly related to
the sizing of the tank. The larger the tank, the smaller the drop in
temperature in the tank when hot water goes out and cold water comes in,
so the smaller the thermal shock each time hot water is used. So, by
using a 60 gallon tank for one bathroom instead of two, you SHOULD
expect to get a much longer lifespan of the tank in that heater. I
don't know if it would be double, but it would be much longer than using
that one tank for both bathrooms.
So, it's a pretty good overall gameplan in my books.
Community Association Underwriters of America, Inc. (CAU), one of the
largest insurance providers in the United States for community associations,
residential and office condominiums, cooperative apartments and homeowners
associations says on their site:
<< How do Water Heaters Fail?
A water heater holds and transfers water continuously - from installation to
replacement or failure. Over time, deposits will accumulate on the bottom of
the tank. These deposits corrode the tank liner and heater elements. Water
quality, particularly water hardness, directly influences the amount of
sediment deposited.
Moving water also causes wear on the tank and piping. The (!!) hotter the
water, the greater the fatigue on the parts it touches. (!!) The constant
heating of cold water also subjects the unit to extreme temperature swings.
No household appliance works under tougher conditions than the storage water
heater.
In most cases, water heaters fail gradually, but not always. Some of the
telltale signs of imminent failure include water accumulation beneath the
heater, a hissing or whistling sound characteristic of a worn valve, and
chronic hot water shortages during periods of normal demand. Prompt
corrective action is required once the signs of failure appear.
When the corroded bottom of a tank fails without warning, the water already
in the tank and the continuously fed cold-water supply create a deluge. If
not stopped, this water will continue to flow. In these cases, it's crucial
to stop the flow of water by turning off the cold-water supply valve at the
water heater or at the water main shut-off. >>
Community Association Underwriters of America, Inc.
http://www.cauinsure.com/
http://www.cauinsure.com/Include/Documents/P3%2520-%2520Minimizing%2520Water%2520Damage%2520From%2520Water%2520Heaters.pdf
I'd say they give fairly serious weight to the thermal shock a unit endures
as a cause of failure. Certainly not 100% but I'd say a fair number of
cracked tanks die from thermal fatigue.
With my limited experience with a water heater "plant" at a photofinishing
plant I QC'ed at, water heaters are indeed sized professionally to never
drop below half. If you run out of hot water, you are undersized in most
cases. I would bet that running low with large amount of winter-cold street
water has a negative effect on longevity very similar to what Nestork
proposes. And it means you have a sizing problem - the tank(s) is not big
enough.
As aside and a thread shift - the tank water heater deluge they mention
could be worse. I think I would rather have a water heater tank crack than
a washing machine hose split and turn into a fu&ing sprinkler. BTDT
Two major upgrades were monitoring and double-hulling the hoses. Now even
the stainless steel braided super high quality replacement hoses are backed
by a Floodstop and by covering them with smurf tube over their length so any
spraying occurs in a sheath and runs down to the floor instead of watering
the ceiling. And the workbench. And the washer. And the dryer. And the
pet food shelves. )-:
More importantly, in case of any gas or power interruption a tank heater has
some reserve hot water. When a tankless unit fails in winter, nothing's
left but cold, cold water. Sadly their rate of failure seems much higher
and rightfully so, they are more complex and run very hot. Also, if you're
the slightest bit a survivalist that's 50 gallons of stored water you don't
have with a tankless. Depending on the disaster, of course. (-:
On Sunday, August 11, 2013 3:26:30 AM UTC-4, Robert Green wrote:
There are tankless that don't require AC power to operate. As for gas
interruption, that occurs so rarely that it's not a factor, at least not
here. I've never had a gas outage. And if the unit itself fails, tank
and tankless are about the same. You're typically not going to know that
the unit is no longer operating until you don't have hot water.
Sadly their rate of failure seems much higher
Good point. I was assuming that all tankless heaters needed AC power. The
addition of the generator turbine indicates that they used to, and it was a
bad idea for reasons we already discussed.
With AC powered tankless models, when there's a power failure, you *know*
you're out of hot water whereas a tank will usually give at least one shower
before it quits, and that's often enough to bridge any power disruption.
If you have an electric tankless, you can not generate enough power to heat
water. A 5 KW generator will run most tank water heaters. You can cut off
about everything but a few lights, run the water heater for a while and
then cut it back off and get another quick shower or two.
Another good reason to avoid tankless. (-: Or at least another data point
to consider when evaluating the two different types of technology. FWIW, my
old pilot-light gas water heater doesn't need any electricity to keep
churning out hot water day after day and that's just the way I like it!
What bothers me most about gas tankless heaters is the large bore supply
pipe that's needed. Lots of houses blow up from gas leaks every year. A
very large supply pipe increases the potential of a serious and very fast
moving gas leak. No thanks!
Thanks for your input, Ralph.
On Tuesday, August 13, 2013 7:04:38 AM UTC-4, Robert Green wrote:
I doubt there is much correlation between a larger gas pipe in
a house and the risk of explosion. Probably more explosions are
from small appliance hoses and their connections than from a supply
line. And even if a 1.5" gas line started to leak, it's usually
at a fitting, or maybe where some corrosion ate through a pin hole
. and I'm not sure it's going to necessarily leak any
more than a 1" pipe. Where it would matter would be if the whole
pipe got severed and that is very rare. Even then, if it's a 1"
or a 2", the result may very well be the same.
I believe that slow leaks and smaller pipes reduce the potential for a fast
build-up of gas without anyone noticing the smell. I saw the results of a
truck backing into a gas meter at a loading dock and remember seeing the
"shadow" of the gas pouring out from the ruptured main on the ground. It
was an impressive amount of gas escaping the broken pipe, but fortunately it
was outside and couldn't build up to. A few years ago a similar event in a
shopping center nearly knocked the entire building down just as the gas
company techs were arriving on the scene. It was caught on CCTV
surveillance video and it was a very impressive explosion.
I'll agree that the chances of a major rupture are small, at least in areas
that don't have frequent earthquakes, but after we got shook with a 5+ quake
in the DC area, an earth-quake induced rupture is not out of the question.
I'd still rather have a smaller gas pipe entering the premises, just in
case.
If for some reason I were to "heavy up" the gas line coming into the house,
I might opt for this:
http://www.tracpipe.com/CSST_Gas_Pipe_Products/AutoTrip_EFV_Automatic_Gas_Shut_Off_Valve/
<<AutoTrip Excess Flow Valves are activated by the unrestricted flow of
gas, resulting from a gas line rupture. This flow causes the valve to trip
(shut down). The bypass flow feature restricts the gas flow to a safe level
upon valve activation. Bypass flow provides automatic reset capability once
the downstream gas piping has been repaired.>>
On Thursday, August 15, 2013 5:31:31 AM UTC-4, Robert Green wrote:
st
Small leaks do reduce the potential for a build-up of gas.
But I don't think there is much, if any difference in the
the size of a typical leak from a 1.5" pipe or a 3/4" pipe.
If the pipe is leaking a little at a fitting, as is typically
the case, probably not much difference. And chance of it
somehow getting severed completely, which would make a difference,
in the amount of gas released, is remote. Even then, if you have
a 3/4" pipe or a 1.5 pipe spewing gas, not sue the outcome is
going to be all that different either.
I'd bet there are far more serious explosions
and fires from the small hoses that connect dryers, stoves and
such than from a large gas pipeline serving the whole house
or a major appliance.
I saw the results of a
That apparently took out the gas meter and had gas spewing out
from the high pressure side. Would have been pretty much the same
thing with or without a tankless water heater.
It
it
a
as
ake
.
But then you already have large service pipes entering homes and
all kinds of buildings. What size service do you think goes into
an apartment building with 100 people? Yet, we're supposed to worry about
a slightly
larger pipe to handle a tankless in a house? Where do you draw the line?
Gas outdoor grill OK? Gas range? Gas ovens? Gas dryer? Gas water
heaters, some houses have two? Gas furnace, some houses have two of
those? Gas generator? They are all OK, but adding a tankless and suddenly
it's so much more dangerous that it becomes a special consideration?
-- More stuff snipped--
But then you already have large service pipes entering homes and
all kinds of buildings. What size service do you think goes into
an apartment building with 100 people? Yet, we're supposed to worry about a
slightly
larger pipe to handle a tankless in a house? Where do you draw the line?
Gas outdoor grill OK? Gas range? Gas ovens? Gas dryer? Gas water
heaters, some houses have two? Gas furnace, some houses have two of
those? Gas generator? They are all OK, but adding a tankless and suddenly
it's so much more dangerous that it becomes a special consideration?
-- Another snip --
Seems to me that knowing how to shut the gas off quickly in an accident or
earthquake would be more helpful than worrying about pipe size. Our main
gas valve is outside by the meter in plain sight. It takes a hefty wrench
to turn the valve which is why I keep a large pipe wrench hanging on the
wall by the back door. I suppose I could also get the special tool for the
street valve; but that sounds like overkill.
Tomsic
Can commoners like me buy a street valve wrench for gas?
I know we can get water wrenches. But gas? Some day I
should pop the cover off a gas street valve, look in
with a light, and see what kind of lug it has.
As to the gas shut off by the meter, they are typically
greased with heavy waterproof grease. I've turned off
valve by the meter with 18 inch pipe wrench.
In case of earthquake, or large fire, a gender neutral
politically correct adult person of nondescript racial
and ethnic origin can save a lot of people a lot of
damage. Just need a good man with a pipe wrench.
.
Christopher A. Young
Learn about Jesus
www.lds.org
.
On 8/15/2013 10:04 AM, Tomsic wrote:
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