In article , Smitty Two wrote:
In article ,
(Doug Miller) wrote:

In article , Smitty Two
wrote:

A house is not a water heater. The overwhelming majority of the energy
used to maintain a water heater comes from *using* the hot water and
heating the replacement cold water. You aren't using the air in your
home, it's leaking out.

How is warm air leaking out of a house -- and consequently being replaced by
colder air leaking in -- meaningfully different from warm water being
withdrawn from a water heater and being replaced by colder water?

The only one who coughed up anecdotal numbers from the real world in
this thread said his electric bill went down by $40 when he switched
from electricity to NG to heat his water.

Plausible IMHO.

Let's say 90% of that money went to heating cold water coming in, which
replaced the warm water going out. And 10% of that money went to making
up for "unintentional" heat loss.

Also plausible.

That's $4, total cost of unwanted heat loss. And let's say that turning
off the WH at night saves, oh, maybe 5% of the energy that leaving it on
all night uses. The OP defined all night as 10 hours.
(10/24)(0.05)($4.00) = $0.08.

I wonder at your guesstimate of 5% ...

I stand corrected. I said the OP couldn't save a plug nickel. My new
position is, he could save *eight cents per month.*

... just off the cuff, I'd regard 20% as a more plausible figure -- which
brings the savings all the way up to a penny a day. Those pennies add up, you
know. ;-)

On second thought, I bet the timer costs .08 to run every month. I'm
going back to my plug nickel assertion.

Depends on which guesstimate is closer to correct: your 5%, or my 20%. I just
had a look at the Dayton Electric Timer which was left here by the previous
owner; it has a 3-watt motor. 3w * 24 hrs/day * 30 days/mo = 2160 watt-hrs/mo
= just over 2 kwh per month. Assume ten cents / kwh; at 5%, you're wasting
money, but at 20% you're saving. Not much, admittedly, but still non-zero.

I'll let you work out how long it takes to recoup the cost of the timer. :-)

You seem like a smart guy, Doug. I think you can figure out what I mean
when I say turning off a WH isn't the same as turning down the house
heat at night.

If by that you mean -- yes, the two situations operate on the same principle
exactly, but the amount of money saved on the water heater is so small as to
be not worth consideration -- then we agree. If you mean something other than
that, then we probably disagree.