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Robert Neville

(Beachcomber) wrote:

For some reason, there is a myth that the "tank" systems are horribly
inefficient and wasteful and that the "instant tankless" systems are
green and more economical in the long run.

Yep. Inevitably every couple of months someone discovers this incredible new hot
water heating system that's going to save them thousands of dollars a year and
thinks it's the solution to world hunger.

For most tankless installations, by the time you get through paying
and solving all the problems, the payback period is going to be a long
way off in the distant future.

People don't look at the total cost of a system, only their monthly out of
pocket expenses. That's why leasing vehicles is so popular.

In the United States, the "tank" systems are a tried-and-tested
commodity item (in most cases) and can usually be replaced in the same
day at low cost. They last for years and the lifetime can be usuallly
be extended if you take care to flush it and replace the electrode at
periodic intervals.

A former AOSmith engineer wrote a great whitepaper on tankless heaters. There
are a few circumstances where it makes sense to use them, but in most
residential applications a standard storage heater is the best solution.
http://www.nyletherm.com/whitepaper2.pdf