Yes mr hallerb, I do have a financial stake in my tankless, it gave me
a 4 year payback over an electric tank, but I only paid under 500 and
did the instal myself. At least this time tankless isnt getting beaten
down completly improperly. But there is no tank to rust, its copper
pipe designed to last 30 years, I ve done no maintenance on mine, but
it is set up to be able to be flushed. But for a family, often a tank
is best. For total Ng efficency no tank can match tankless by at least
10%, even condensing AO Smith units, And guess what, now AO Smith make tankless.-

so your comparing the savings of a regular electric tank against a
natural gas tankless......???????

guess what nearly anywhere in the country a natural gas heater will
save money over electric water heating. sure electric is 100%
efficent, but per BTU electric is super expensive to operate.

If I were the OP I would investigate moving the tank to a new larger
location, and going with a condensing 98% efficent condensing tank
heater. outside air is drawn in, so interior air isnt burned for
combustion, and the exhaust just like a condensing furnace exhausts
thru a PVC pipe. Install a drip pan in case a leak would cause damage.
most condensing tanks have copper coils inside the stainless tank.
this leads to extremely long life.

previously ransley has talked about servicing his tankless. and his
claim of 30 year life is pure bogus. tankless use sophiscated parts,
which one day may be no longer availble, poof gone, no parts no hot
water.......

Here we just replaced our 1965 furnace with a condensing one, next up
will likely be a new condnsing water heater. our existing tank is 8
years old, it had a 6 year warranty.

with the rising cost of energy we should all do what we can to save $$
$.

also looking at gutting part of our house, and adding spray in place
foam, along with wiring and new kitchen......