On Aug 7, 11:50*pm, Smitty Two wrote:
In article ,
*"PanHandler" wrote:
"Smitty Two" wrote in message
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Sorry, peak hours are *not* at night. I'd venture that 99% of the DOE's
supposed savings is due to a reduction in the price per kwh. Not only
that, they aren't talking about your *total* electric bill, only the
portion of it that the WH accounts for. So the logic behind your $8
savings is flawed.
This problem is a minor modification of the jacuzzi heating question,
and the same logic applies. Every speck of heat lost through the night
has to be replaced. Do it in small chunks, or do it all at once. Same
amount of energy is expended, disregarding the *very* minor difference
noted (that rate of heat loss decreases as temp. differential decreases.)
Please reply to my earlier post:
Compared to being on all the time, how could it not save me substantially if
it only runs thirty hours a month? It seems to defy logic.
Thank you.
Perhaps the confusion stems from some ambiguity in the word *on.* An
electric water heater is not *on* all the time anymore than a
refrigerator is *on* all the time, or a motion sensor light.
The refrigerator is triggered to come on when the temperature rises
above a certain threshold. The motion sensor light is triggered to turn
on when motion is detected.
And the water heater is triggered to come on when the water temp falls
below a certain threshold. The fact that it hasn't been "turned off"
doesn't mean that it's consuming electricity.
Let's say that between a shower and other needs, and heat leaking to the
surroundings, your tank loses 50 degrees in 24 hours. And let's say it
can make up that 50 degree loss in an hour.
It will use just as much electricity if it comes on for one hour every
day, making up the whole 50 degrees at once, or if it comes on for six
minutes, 10 times per day, increasing the water temp in the tank 5
degrees each time.- Hide quoted text -
- Show quoted text -
Despite your post acknowledging that this was not true, where you
seemed to recognize your earlier posts were incorrect, here we go
again. In your above example, yes the water heater uses the same
amount of energy because it runs for only 60 mins either way. The
big difference is that in the case of the frequent reheating, at the
end, you wind up with a tank of water that is at a slightly lower
temp. You seem to have a problem confusing what may be practical and/
or worth doing with pure physics. The amount of heat loss is
proportional to the temp difference. If the tank is reheated
frequently, or just left on to maintain the normal temp, the tank will
be losing MORE energy as heat loss. Therefore at the end of the
period, it either uses more electricity to get to the same temp, or
with the same amount of electricity ends up at a lower final temp.
If things worked as you claimed, why is setting back the temp of a
house overnight effective in lowering energy usage? It's the same
thing. The energy lost over night has to be made back up in the
morning when it recovers. Following your logic, there would be no
savings. But of course there is. The exact same thing holds true
with the water heater example, but the difference is smaller.
Now, you can argue whether the savings are enough to warrant doing
it. But you can't argue the physics, which you appear to be doing by
your mistatements.