Hi,

I lived with these cursed things in Europe during the '60's and
thought a little explanation on how they worked at that time might be
helpful. There may have been improvements made since, can 't comment
on that, but the basic principle of their operation is not subject to
change. I imagine they are still in common use there.

They were invented not to make life enjoyable, but because what we
call energy these days, even then as today, was and is extremely
expensive in Europe. How does $8.80 for a gallon of gas strike
you? , the Norwegian price the last time I checked recently. I got
used to paying $4 to $5.00 a gallon for my car's gas. When heating
oil was $.15 here in the USA, I was paying $.21 in Munich.

So "tankless water heaters", I was told, were common here in the
States early in the 20th Century when the standard of living,
particularly among the numerous impoverished new arrivals found our
energy expensive, but eventually the tankless all but disappeared as
our standard of living rose over time.

It all comes down to money. The American conventional "hot water
heater"- a misnomer - is by its very nature, a wasteful device, no
matter how well insulated. After all, there it stands 24/7, 40 or
50 gallons of hot water you've paid to heat - doing absolutely
nothing but giving off heat - until you open a faucet. It's their
convenience that made their popularity.

What are the alternatives intended to save money? One is to have
your boiler, ie, hot water house heat, have a heat exchanger within
the boiler water jacket to heat your hot water storage tank. Which
means even in August temperatures, your house heat boiler has to fire
up to provide heat merely to heat the hot water storage tank. Excuse
me???? Folks heating with hot air are spared the benefits of this
approach.

Another alternative is the "Tankless Water Heater" where there is no
big tank of hot water standing there doing nothing most of the time,
but giving off expensive heat. Wonderful idea.

But reality intrudes: The way the tankless are built is, #1, They
must have a source providing humongous instant heat, in short, a
gigantic gas or electric hot plate. What they heat is what you get
in real time at the hot faucet - or shower. #2, They have to have a
way to get that "hot plate" heat into the water to your hot water
faucet - which means a big copper coil is also incorporated. If
heated by gas the roaring fire will be under and around the big
copper coil. If heated by electricity, there will be an immersed
heating coil instead. So, by their very nature, tankless water
heaters are not exactly tiny.

"Hot water created at the point of use?" Which is the tankless
heater's major selling point - (but they can be installed in the
basement or attic.)

First of all, if gas fired, each one requires an outlet flue, and a
gas connection, same as your gas furnace. (Unless you favor carbon
monoxide.) Or, if heated by electricity, they each will require a
dedicated heavy electrical cable, much like an electric kitchen range.

Then there's the audio joy if gas heated - like a jet airplane
engine flame-out every time you open a faucet for hot water, as the
gas hot plate comes on with a big "Galoooop!" sound. The
electrically heated types are mercifully silent.

And with the genuine element of possible personal danger if in close
proximity to a gas type coming on. A couple, friends of mine in
Paris, with a wife who was very proud of her gorgeous head of hair
was washing dishes at the kitchen sink, tankless heater on the wall
above, leaned in to open her hot water faucet, the instant tankless
came on - and her hair was instantly set on fire.

The tankless heaters operate by sensing a slight pressure drop in
the water pipe to the faucet. When you open a faucet there is a
slight pressure drop in its water supply pipe. This sets the heater
going, and you do get instant hot water at that faucet. But my 40
year old experience was, what temperature hot water do you want? If
you fully open a faucet, you'd better have a tankless large enough
to keep up. I used to vary how hot the water was by closing down
the faucet. Really hot water? Don't ask for too much flow.
Warmish water, open 'er up, let 'er rip! So hot water temperature
was faucet volume sensitive.

Then there's the final surprise. Because drop in water pressure
controls the tankless which is generating the hot water, they can be
"one-faucet" devices! Remember, "Hot water created at the point of
use?" You're in the shower and wife opens the hot water faucet at
the kitchen sink - 'nuff said, unless she also has her own tankless
for the kitchen sink. Or you have one giant tankless.

So your house has six devices needing hot water including dishwasher
and clothes washer? You'd better order six tankless heaters or one
giant size. If giant size, which single device, or which assortment
of simultaneous hot water devices will collectively control that one
single water pressure sensing valve of that one giant tankless?

I can offer nothing regarding tankless reliability. Look elsewhere,
please.