These are very common in Europe. I lived over there for years and always had
hot water instantly. Of course, the manunfacturers available here likely
different from Europe. It's best to talk with someone in the area who
already owns the one you are considering.
Tankless water heaters were a standard "low end" product when I lived in
Asia (~15 years). The better apartments had hot water tanks.
My experience with gas-powered tankless heaters is that they are, indeed, a
low-end product, where the primary advantage was that they didn't take up
any floorspace. (The average apartment in Asia was about 600 sq ft total,
so every inch of space was used.)
People on this thread are asking the right questions, especially about flow
rate. In my experience it was difficult to balance temperature and flow
rate; when you decreased the flow of hot water to get a comfortable
temperature, you could reach a point at which the gas suddenly cut off and
you went to full cold. Given the low cost and reliability of conventional
hot water tanks, I don't think the pay back period of a tankless heater is
I suspect installing a tankless water heater is a little bit like buying a
diesel car, being responsible for the two happiest days of your life -- the
day you first start to use it, and the day you finally get rid of the
When we remodelled, I chose instead to put an additional hot water tank
adjacent to the new bathroom, which gives me almost instant hot water.
Temperature and flow rate is now computer controled with a full
modulating gas valve so temp stays the same when it is on from start to
full flow. Older units lacked this. at very low flow it will turn off,
that is a drawback but it doesnt bother me as all my faucets are low
flow so I ususly just turn them on full. My payback will be 4-5 yrs
switching out an electric tank. I have no complaints after 2.5 yrs.
Yes - the new tankless units are nothing like the low end stuff we saw
in the past in Europe. Today - the new units are computer controlled -
and are relatively bulletproof. Some are 92% efficient. They have
digital wall gauges that allow you to tune in the temp you want within
I am planning to replace two 50 gallon electric water heaters with one
unit - Rennai - Bosch - Akagi.
My city give a $450 rebate for converting and electric water heater to
gas - so I may put two in the house - that way I have one as a back up
Tankless heaters now have computerized controls that eliminate the wide
temperature fluctuations you experience with the older models. I was also in
Asia during that time frame and remember how quickly I woke up after taking
a shower where the water temp swung 40 degrees.
My neighbor has a big house. He had two gas tank water heaters. He
replaced them with two "takagi" tankless water heaters - had them
installed for $500 each. Now this guy is a wealthy fellow and money does
not matter to him - service does. The tankless water heaters produce
endless instant hot water - no lag - no nothing - turn the faucet on -
hot water comes out now. He can have four showers running at once and
the hot water still does not run out.
The units are very small - less than 2 x 2 x 1. they do not require
electricity - so you have hot water even in a power failure. They have a
A restaurant down the street has one. They do piles of dishes daily.
They depend on that "rennai" tankless water heater. It does a great job.
their business would go down without it. they have been using it two
years without one down time.
Also - since we leave our home a lot - we will not be heating a tank of
water and wasting energy keeping it warm. When you are away - everything
is off. It only turns on when you turn on the hot water faucet. I am
going to install my tankless heater on the outside wall just 4 inches
from my showers.
Also my city will give me $450 for every electric water heater I replace
with a gas one - so this is an easy decision.
The new technology in tankless water heater is fantastic. Yes -
conventional water heaters are cheaper than tankless - but but tankless
are cheaper to run and much more efficient.
I am going to install one or two.
Not only no standby loss but no pilot loss and no thermal loss on pipe
to tank. My small Bosch is 2 D cell battery ignition, no pilot.
Effecienceis of tankless are 81 - 94%, 94% for the new Takaki. Tanks
calcify on the bottom with scale. I recently removed a tank in my apt
building on relativly soft water. There was 14" of scale in the tank,
now that kills efficiency. Tankless dont loose efficiency as tanks do.
There are many sites showing individual units efficiencies. Overall
going from electric tank to Ng tankless my bills are down 75%.
In raising X amount of water Y degrees. Yes.
But that's not all there is. What about all the energy you waste
when extra hot water you've had to run for 60 seconds to get _any_
warm water to the tap, sits in the pipes overnight? With tankless,
that's not an issue.
Efficiency, to mean anything, has to include the whole system. Including
heat loss off the pipes.
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
Dear Rich -
No matter what we say - you are not going to be impressed. That fellow
told you he saves 75% on his tankless gas water heater - but your mind
is made up. We don't want to argue with you - if you don't agree - don't
buy one. But we have studied this to the point of purchasing them. My
neighbor put two in just a few months ago - and loves them. You seem to
just want to argue. I do not like evangelists that try to convince folks
to do something pro or con - especially when they have nothing but a
cranky opinion - but no data to back it up. On top of all that - my
city likes them so much - they are willing to give me $900 in rebates
just to install them. As much as I value your opinion - please present
information showing that tankless heaters aren't as good as tank types.
I am willing to listen to other information - my mind is not closed -
but it must be more than someone just arguing for argument's sake.
Thanks for caring about us so much to try to convince us not to make a
If you get one with a standing pilot sure there is the pilot loss. That
is the Bosch 80-81 % units . From pilotless efficiency goes from 82% up
to 94% depending on unit and manufacturer. Harry E., Rich Kinch has
been all over trying to put them down and calling companies like Bosch
fly by night. Bosch should anyone care to look at a company report is
like our GE or GM , big and established.
Kinch probably can`t afford one so this is his justification and cuts
them down baselisly
As regards efficiency, I did: simple thermodynamics, time, and space.
Heat exchangers become *less* efficent as they get smaller and faster,
I am not an "evangelist". I am a skeptical engineer, with reasons to be
skeptical. The burden of proof is on you if you claim the old ways are
Look at the hucksters and swindlers that sell these things.
Look at the testimonials instead of metered testing.
Look at the performance claims that defy elementary BTU calculations.
Look at the absurd claims about how bad conventional units are.
Wrong. I am impressed by facts and analysis. Not testimonials that
defy freshman physics.
This is exactly the response of those who won't accept the truth when
the truth doesn't fit their candyland ideas. This is the response of
advocates of perpetual motion machines, 100 mpg automobiles, 50000X Rife
microscopes, lifetime paint, magnetic water softeners, septic digesters,
$1200 boom boxes, bagless vacuum cleaners, waterless cookers, light
bulbs that don't burn out, plates that don't break, stuff to pour in
your gas tank to fix your engine, knives that never need sharpening,
glue that sticks to everything, and the fountain of youth.
Show me some engineering analysis and testing. Guys with meters and
thermometers who aren't trying to sell something. Not sales
brochures, not testimonials, not reports from across the ocean in
another alphabet and language. Loan *me* and unit and let me run it
through my laboratory.
Show me somebody in the USA who makes these things that I can sue when
their claims of 75 percent savings is proven to be the bunk that it is.
I was told by a plumber that if I wanted one of those, I would also have to
replace my 1/2 inch gas line with a 3/4 inch line which would add
considerable cost to an upgrade. check on the requirements of the heater
you want and the size of your supply line to know if this will be an issue.
I am also interested in these tankless heaters... What concerns me is
the minimum flow rate to trigger the heating action... Would a faucet
that was not on full blast (ie a trickle for washing dishes) be enough
flow to trigger the heater?
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