They're very small. They only come on when you open a hot water faucet. They
use lots of electricity or gas while they're working to keep up with the
demand, but none when there is no hot water flowing. The benefit is that
your not paying to heat and store a big tank of hot water. Sizeable units
are expensive to purchase and you need an adequate electric service or gas
service to operate them
Thanks. I am looking for someone who has or had one and can recommend a
brand name. Already did my search on the Internet and know everything
the websites are suggesting, this is why I need a person who has one,
and that is not to say that your advice wasn't sufficient because it was :)
Yes; Takagi. I just helped install one (I did the wiring, a real plumber
did the rest). This apparently is *the* state-of-the-art tankless heater
currently. The model we installed is pretty kewl, in that it is made for
exterior installation and requires no venting (it vents from a small
grille near the top of the unit). Very efficient, compact (surprisingly
small) and well-made.
This one also has electronic ignition, so uses no gas at all when not
needed (unlike older ones with pilot lights). The only downside to this
seems to be that it will not work during a power failure; there seems to
be no way to manually light it.
Advice? Ya, don't bother. You'll never get the water hot enough
(especially in the winter) to wash dishes properly. Even hot enough for a
proper shower is questionable. And don't even ask about the flow rates.
gas or electric? if electric just forget it, unless your willing to
upgrade your main service to 200 amps just for heating water. can cost
gas? delay from valve open to hot water arrives, heater must detect
water use then turn on burner. you will waste water.
with low flow valve open a little to wash dishes may not be enough to
trip on burner, cold water a result.
if your tankless needs line voltage to operate a power outage means no
hot water at all. a standard tank still has a tank full to give, for
say 2 quick showers.
tankess warranty is no longer than a regular tank. you need qualified
service people they are complex. standard tanks are highly reliable
till they leak, at which point you replace them...... nearly no
if you live in a area that gets cold, incoming cold water can cause
tankless troubles when water gets really cold. around here it bottoms
at about 40 degrees.
the tankless savings are bogus, regular tanks standby losses are
really low, take a look at the energy guide. in the lifetime of a
tankless you will save little because of the large up front cost.
oversize gas line, high capacity flue/
in the winter standby losses help heat your home
endless hot water can get some folks to live in the shower, driving up
water and gas use........ teenagers are the worst.
20% of the Standby loss goes up the uninsulated center part of the
tank, up the chimney, and does not provide additional heat to your
home, thats why 50-60 is the true Energy Factor rating, or what you
get out of every dollar you put in.
I don't have a citation, but it is easy to derive this number. A
typical 80% combustion efficient gas tank water heater has an energy
factor of 0.60. The energy factor of 0.60 means that temperature rise
of the hot water delivered during the standard 24 hour test period
represents 60% of the theoretical heat content of the natural gas
burned during that period. So 40% of that theoretical heat content is
lost to the user.
Since the combustion efficiency of the burner is 80%, 20% is lost as
soon as the fuel is burned. The other 20% represents standby losses.
Most of this is due to air being warmed as it rises through the flue.
For example, a good electric tank water heater might have an energy
factor of 0.93, and such a tank has no flue. So through the outside
of such a tank, 7% of the theoretical heat content of the electricity
used is lost to the user. Thus we might infer that for our gas tank
water heater, likewise 7% is lost though the outside, meaning 13% is
lost up the flue.
These numbers are rough and depend alot on the amount of insulation on
the outside of the tank. But obviously there can be no insulation
along flue or heat exchanger, so that is a large source of standby
Look up Energy Factor ratings on WH, Your burners are about 80-83%
efficent on non condensing units but Energy Factor which is the true
Energy rating taking into account heat loss are on average 60 for Hw
tanks. The center is uninsulated and goes out the chimney. Foam
insulation on tanks are very good and heat loss through the insulation
is minimal, the real waste is up the center and out the chimney.
Tankless Energy factor is the burner efficency rating mine is 82, no
tank does that well except electric. so compare all 3 tankless,
electric and gas , the difference in electric to gas tank is the
center flue and it adds to a 20% - + loss.
Replacing a 0.60 EF (Energy Factor) tank with a 0.80 EF tankless
should reduce your usage by 25% (1 - 0.6/0.8). That assumes your
usage pattern matches the standard usage pattern of the the EF test.
If your usage is less than the standard, your savings will be higher
(as the standby losses will be comparatively greater), while if your
usage is greater than the standard, your savings will be less.
Truth. But there are a number that don't need line voltage.
Dead flat false. We have two hot water heaters in the house. We replaced one
with a tankless. Our summer gas bill promptly halved (both dollars and volume).
The heater we replaced services the kitchen and laundry where the hot water use
is fairly low, so standby losses are a large percentage of the cost. I figured
a five year payback, much less with gas cost up.
And raise your air conditioning bill in the summer. Or do nothing if the heater
is in unconditioned space.
When our twenty something daughter moved out, both the gas and water bills took
a significant drop. The tank water heater has enough recovery to feed a low
flow shower head all day. Sigh.
Mine operates sucessfully 2 years with the original 2 D cells for the
Battery ignition - No AC Needed, no power vent. Its amazing how many
Lian Miss informed ASSes will put down a Tankless since the either
they " dont sellem" "Dontservicem" and what ever Biased, BS, LIAN,
reasons I can`t figure. What Bull Shit these Crap Heads, Shit Heads,
are, yes full of Bull Shit......Obviously TANK sales employees or
orther idiots, associated with TANKs..........
How far back does your newsreader go? There was a long thread on this
Subject: Most efficient water heater?
Date: Sun, 16 Mar 2008 20:27:22 -0400
Don <www.donwiss.com> (e-mail link at home page bottom).
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