On Apr 15, 12:23 am, Richard J Kinch wrote:
Caya writes:
Any ideas?

28 KW (37.5 HP) and weighs 30 lbs? Are you mad? That's energy density
comparable to a jet engine. Not something I want running in my house.

To heat water to 120 deg F in a Yankee winter (delta_T = 80 deg F) takes
40,000 BTUs/hour for each gallon per minute. That's 11.7 KW per
gallon/minute with perfect efficiency. So a 28 KW unit (if that much is
to be believed) will get you 2.4 gallons/minute of hot water. After
tempering to bath temperature with cold water, you will be just over the
piddling water-saving "shower" rate of 2.5 gal/min, which will waste
many minutes of your time every day (or however often a rube who is
foolish enough to buy tankless bathes) for the rest of your miserably
shower-impoverished, life.

Also consider that electric demand rates are typically $12 per KW each
month. So to just turn on this 28 KW fantasy costs you $336 per month!
Or it would if your residential electricity weren't subsidized for free
demand. This is after you have paid $1000s to upgrade your electric
service by 100+ amps to operate this rocket engine gadget that runs like
a tricycle with a bent wheel.

Tankless heaters are more expensive to buy, more expensive to own, and
more expensive to operate. Anyone who selling you a different story is
a fraud. This is not a case of sales puffery or exaggeration. This is
outright flim-flam baloney that flies in the face of physics. The
reason the Web sites and newspaper ads look like they were designed by
hillbillies after a quick buck is, they were.

I agree and was struck by this:

"The old tank was ancient, and needed to be replaced. It was eating up
a
TON of electricity"


Physics would suggest otherwise. Whatever electricity the tank water
heater was
using was all turned into heat. Exactly the same as the tankless.
The only difference is that the tank water heater lost some of that
heat through loss from the insulated tank to the surrounding air while
the water is sitting there, waiting to be used. That amount isn't a
ton, especially in an
electric unit that doesn't have an exhaust flue running up the
middle. New tanks have
more insulation and you can add a cheap extra insulation blanket if
you want. I agree with Richard, that I doubt you will ever recover
the increased upfront cost of a tankless in future energy savings.

And I would be very surprised if you see any significant change in
your electric bill. BTW, in some areas, electric companies offer off
peak service meters and rates for water heaters. Meaning they charge
a significantly lower rate since the water heater won't heat during
peak day time hours, which is something many people find possible with
a tank heater. If available, you can't take advantage
of that with a tankless, so a tankless could cost a TON more to
opperate

In my view, the main advantage of tankless is when you have a unit of
sufficient capacity to meet all your needs and have a usage pattern
where you would run out
of hot water frequently even with any reasonable size tank heater.