I've detected some leakage around the base of our hot water heater. It's a
75-gallon Rheem and is at least 10 years old. I suspect it's time to repl
ace. Any of you have experience with a tankless system? How fast does a t
ankless system deliver hot water?
Like any water heater, it depends on how close it is the the faucet you
If it's installed across the wall from the kitchen sink, for example,
you will have hot water almost immediately after the cooled water runs
out of the pipes.
There's not much water running through the heat exchanger inside them
and it heats it extremely fast.
"Playing is not something I do at night, it's my function in life"
I think you know what you are talking about but just as much water goes
through a tankless water and its heat exchanger as does a tank type
water heater. The the big difference is that you are not heating water
that is not currently being used and only the water that will be used at
a given point is being heated.
When we lived in Sicily there was an antique one installed in the
outside laundry room (thankfully). When you turned the hot water on
that thing fired up like an F-16 and ran until the hot water was shut
off or the propane tank--bombola--was empty. Worked fine.
In Japan there are a lot of them. They are more modern and smaller.
Usually you would see a little one hanging on the wall over the
kitchen sink. Never saw an electric one but I'm sure they exist.
Would have installed one on the boat when it was time.
How close is the "load" to the heater?
How soon you get hot water is dependant on how much cold water
you have to push out of the way to get to the hot water.
Same as with your existing set up.
Also they need to be cleaned at least every two years or mineral
buildup can become a problem.
I love the way our electric provider shows us how much of our electric
goes towards heating water when there is nothing on the house to
actually capture that data. I have told them to stuff their bogus
statistics and focus on cost-savings they could pass along to the
I expect to be replacing my tank with a tankless. I have two friends
in line for that and one already switched over. One is adding small
heaters under sink(s) since they have a longer line to travel and want
hot instantly from turn on. I have shorter lines and expect it to be
the same as it is now, minus the electirc cost (going gas).
It would seem to me that an obvious solution to the inconsistent water
flow and temperature would be to put in a small insulated buffer tank.
When the call for hot water comes, the demand is satisfied initially from
the small buffer tank (5 or 10 gallons?) and the on-demand works to keep
the buffer tank full.
Did I just describe a "hybrid" water heater?
My little point-of-use unit has issues with flow rate as well. The way
it's designed, the flow rate of the water controls the temperature. If
you get just enough flow to turn it on, the water comes out extremely
hot. Also, if you start mixing in cold water it's easy to get to the
point where there's not enough hot flow to keep the unit on.
Admittedly, this is an older unit (it's at least 7 years old, probably
closer to 10). We are also about 100' as the crow flies from the well
pressure tank, so add another 50' or so for pipe runs.
I have long advocated small "point of use" electric water heaters to
provide "instant hot water" for convenience. They can be on a timer to
make sure you have hot water on demand when you want it and still save
power by not maintaining hot water when you don't need it - or to only
run the heater in "off peak" if you are on time of use billing like we
are in Ontario. The payback in not putting 10 gallons of water down
the drain waiting for it to get hot can actually be pretty quick,
depending on the cost of municipal water and sewage services.
By "point of use" I mean a standard small tank heater -something
like 5 gallons close to the point of use. In a bathroom at the far end
of the house from the water heater, for instance - or an upper floor
bathroom. Have it come on 2 hours before you get up so you have hot
water to shave and shower- and let it shut off when you go to work -
then come on an hour before you come home to make sure you have
available hot water to "freshen up". A well insulated tank will
maintain the water temperature fairly well with the power off if no
water is drawn, so you are never reheating an entire tank from cold.
OK... so let us say that you get "point of use" 5-6 gallon water heater to
run in addition to your regular unit to save money and use the timer scheme
. I'll bite.
BTW Larry, a 40 gallon with do for two people regardless of those pesky dog
s taking so many showers!) as he is looking at now. Check the posted energ
y ratings and projected cost of use on the tanks and you MIGHT see a bit mo
re savings over the life of the heater. Probably not too much, but it depe
nds on local energy costs.
So, Larry is in for $1000 for his straight replacement, give or take a coup
le of hundred depending on his site conditions, code requirements, permitti
ng fees, old tank disposal fees, etc.
Check the prices of a 5-6 gallon water heater and you will see they are abo
ut the same cost as a 40 gallon, about $275 to $300. Add fittings, about $
325. You will be giving up closet space somewhere to place this unit, and
will need to install it according to your local codes (read: permitted job
since it is new). You will be cutting into walls to splice into the hot wa
ter system, blocking off the flow from the rest of the house so you don't g
et a cold mix, then splicing into the supply line to get water to the fixtu
re. Would you do that for your shower, too? Double the plumbing cost, so
I would say about $750 for cutting into the walls, cutting into the pipes t
o splice in the new supply route and head off the old supply, and install t
he new water heater. Add more if you are going to try to tie in the shower
as you will have to do supply it as you did to the lavatory.
You are now about a $1000, $1100 bucks. But, you now need to have your ele
ctrician run a 30 amp circuit to this new unit (you weren't thinking of pip
ing in gas with your remark of the unit turning off and on by itself). Do
you have room in your circuit box? How hard will it be to run a new circui
t across the house or upstairs through the walls to get it there? My elect
rician could probably do something like that for about $1500 or so. Don't
scream bullshit! Remember, <<10ga>> copper wire all the way, a new 30 amp
breaker, a new 220v plug/box/cover and a pigtail as well as a 30 amp servic
e rated timer have to be purchased and someone will be fishing wire and cra
wling through attic insulation to get it where you need it. Fishing 10ga d
own a wall is no picnic.
Will you be repairing the demolition you did yourself to allow access to yo
ur piping yourself? Maybe if you have the time, the inclination and the sk
ills. (I can do anything on site with wood but I really suck at tape/float
, myself.) You might need to add a little to your estimate for sheetrock re
pair, wood work and paint on top of the plumbing and electrical. $500?
With you doing the demo, cleanup and replacement yourself, you are going to
be in at about $2600 or so for the "point of use" system.
How long would it take you to accrue the kind of savings you anticipate to
get to $2600 for its recovery? Remember too, there is NO consideration for
the extra annual power usage for the POU unit, and even if it is just on 6
hours a day that is still a helluva hit for an electrically powered water
If you would, please take a minute and explain how long in real numbers it
would take to pay off this machine, and don't forget a probably $ 20 a mont
h ($240 a year) for its operation (that is a very minute .66 a day, only .3
3 per cycle!)when explaining.
My HUD classes told me that in a retrofit for energy saving updates, they s
hould all pay out in 3 to 5 years or they aren't worth doing for a number o
f reasons. A water heater is an appliance, and it falls in the 5 year cate
gory. So if we take your project at $2600 (remember, you do he demo/rebuil
d/job cleaning) and add in $1200 for energy use in the same period (the cos
t would never go up, right?) we now have a $3800 bill for a five year payba
That's $760 a year. Really? That is almost $65 a month in hard cost expen
se for five years. That means your investment wouldn't pay off unless it w
as actually saving you that much every single month for FIVE years before y
ou realize one dollar of gain to recover your investment.
How is that supposed to work? You have seen all my numbers and how I arriv
ed at them. Seriously, I would like to see how you arrived at the point of
thinking this is a good idea and how you justify your dollars spent vs. th
e savings gained. I would love to the "point of use" scheme justified for
an existing home.
On 7/12/2014 3:00 AM, firstname.lastname@example.org wrote:
And that's being generous. I could be way off but the numbers I've run a
few times in the past for various clients and situations indicated a
realistic payback expectation of 15 to 20 years.
Still, discussing that fact with clients doesn't seem to have an impact,
so my conclusion can only be that going tankless to some folks is
culturally equivalent to driving a Pious... er, Prius.
It can certainly be a selling point, depending upon the socioeconomic of
Something I did to get hot water to the faucet more quickly through
galvanized pipes was turn the heat up at the heater. One of the reasons,
especially with those heavy pipes, that it took longer to get hot water to
the faucet was because the heavy pipes absorbed the heat from the water.
Hotter water cooled less getting to the faucet and heated the pipes more
quickly. Yes we had to be more careful with the hotter water. Did I
notice an increase in electricity usage? Not that I recall. You use less
hotter water than not so hot water.
<excellent analysis - snip for brevity>
For those who want instant hot water as a retrofit, they might consider the
A friend just went through the details of tank-less versus tank type
and the deciding factor in going with a tank was that the heater only
raised the temperature of the water a fixed amount and his well water
was too cold to get really hot water. 95F - 100F was about all he
On Sat, 12 Jul 2014 01:00:54 -0700 (PDT), " email@example.com"
Lots of 15 amp 115 volt nominally 5 gallon water heaters available.
Home despot has Ariston Model # GL4.0 4 gallon 1500 watt for $250. It
will fit under the vanity sink. In my house it would require pulling
the vanity, opening the wall and 1 sq ft of flooring, and less than 6
feet of copper pipe to service both the sink and shower ( the shower
would still have about 12 feet of half inch copper full of room
temperature water to purge - a lot less than 45 feet currently
required) - and mine is a SMALL house.
Adding another 15 amp circuit in would be relatively simple as the
washroom is at the end of the house with the electrical service. It's
a job my Dad would have done in a couple hours as an experienced
electrician - and my old panel (soon to be replaced with a breaker
panel) still has room for at least 2 more circuits. Less than 50 feet
of 14/2 or 12/2 would do the job - not prohibitively expensive. I've
seriously considered doing it but we'll likely be moving in the next 5
years if we can find a bungalow we like - and in a Bungalow it's a
whole lot easier yet to accomplish.
On Sat, 12 Jul 2014 01:00:54 -0700 (PDT), " firstname.lastname@example.org"
I replaced the 40 gallon hot water heater last year, looked at doing a
gas replacement for the electric. Routing the piping (pvc) was not
possible without demoing the 1/3 of the basement ceiling and moving
HVAC. Tankless electric big enough to handle the load required a 100
AMP circuit. So went with a 6 year warranty 40 gallon, cost was around
$350, plus about $15 for diaelectric connectors.
On Sat, 12 Jul 2014 13:24:06 -0400, email@example.com wrote:
I'm seriously thinking about doing the same, though it's even easier
in my case. There is ~70' of pipe between the water heater (in the
garage) and the master bath. Both are on the first floor and the
basement is unfinished. There are loads of blank breaker slots in the
entrance panels (slowly using them up for the shop, though ;-). It
would be a simple matter to strap a point-of-use water heater to the
joists (though they are manufactured I-beams), next to a wall,
Sounds like the one he was considering was simply not big enough for the
demand he expected to place on it. I would be very surprised if the unit
was purposely designed to raise the water a fixed amount above the actual
temperature of the water. While well water is cold, that is not a unique
situation. The water coming from a normal/regular water supply can be
close to freezing during the winter months. Regardless of where his water
was coming from I suspect there were other unique variables that were going
to limit the ultimate temperature of the water at the faucet, too small of
a unit being my first guess.
There is a limit to what the temperature can be raised. That is one of
the complaints I've heard with people that have very cold incoming
water. Electrics have less capacity. I've seen them at 36kw or 122,000
btu. From what I saw, you can get 65 degree temperature rise at 3.8 gpm
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