On 10/14/2014, 7:13 AM, Jeff Liebermann wrote:
On Tue, 14 Oct 2014 07:43:04 +0100, Charlie+ wrote:

Interesting, I am UK based and energy costs here are probably much
higher here than in US which may alter the costings so much that a heat
pump wont be feasible for you...
....

Incidentally, you might be amused at how water heaters are rated and
priced. A few years ago, the bottom of my 40 gallon electric water
heater filled with calcium carbonate causing the lower heating element
to blow out. It was rusted in place and not easily replaced. The
heater was old, so I decided a new heater was best. I went to the
local Home Depot store and noticed that heaters were rated and priced
by their warranty life as 6, 9, and 12 year heaters. Current prices
a
http://www.homedepot.com/b/Plumbing-Water-Heaters-Residential-Electric/N-5yc1vZc1u1Z2bcu0t?NCNI-5
$248, $338, and $548 respectively. I asked what was the difference
and received a few bad guesses. The weight of these heaters was
exactly the same, so there was no difference in tank design or
construction. The 6 year heater used lower power elements, but that
shouldn't effect the cost.

I eventually determined that the primary difference was the anode
protection rod in each heater. The 6 year heater used a very small
anode rod. The 9 year used a much larger anode. The 12 year had dual
anodes. The problem was the rods cost about $25/each which is
reflected in the $100 to $200 price difference between the three
models. The 6 year heater had the port for the 2nd anode sealed shut,
so I bought the 9 year model, and added a 2nd anode for a cost of
about $25. Net savings from the 12 year model:
$548 - $338 - $25 = $185
I also installed a permanent drain line, so that the calcium carbonate
will not accumulate again.

Of course you should change your anode every few years - assuming you
can extract it. The house we bought last summer has a replaceable anode
but I can't unscrew it. The tank will fail in a year or two, but then
I'm looking for one with a replaceable anode and do a bi-annual change.

John :-#)#


But if
your electricity costs are low then the payback time on the equipment
may not make sense just for a little domestic hot water... Ground
source is much more expensive on the outlay than air source! C+

Yep. That's the problem. The most efficient system is not always the
most economical.





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