farker?

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"DerbyDad03" wrote in message
...
On Nov 26, 2:13 pm, wrote:
On Mon, 26 Nov 2007 11:01:39 -0800 (PST), DerbyDad03





wrote:
On Nov 26, 12:29 pm, wrote:
On Mon, 26 Nov 2007 11:23:56 -0600, "Steve Barker"

wrote:
the water leaves the heater at a certain temperature. It's not going
to get
hotter, i don't care if you wrap 12 inches of cellulose on it.

There is heat loss from the pipes between the heater and the tap.
That's why the pipe feels hot if you touch it. Insulated pipes may
result in the water being closer to the original temp when it reaches
the point of use. In other words, the water at the tap will be HOTTER
than if the pipes are not insulated.

This is all off the top of my head, with no underlying data to
substantiate my theory...

I submit that in a residential environment, the amount of heat loss of
the water traveling through the pipes will be less than can be
accurately compensated for by the thermostat knob on the water heater.
We're not talking about precision instruments here, and even if you
could adjust the stat to compensate for the "reduced heat loss" the
amount of heat loss is so minimal that that the payback period for the
insulation would be extensive.

There are many variables to consider. How often is the hot water
called for? Does the pipe completely cool down to the ambient temp
between uses? Copper is an EXCELLENT conductor of heat. Notice how
long it takes for the water to reach it's maximum temp at the faucet
when you turn it on. It starts out cold, and it takes some time to
reheat the pipe before it gets really hot.

-- Regardless of ROI, the water at the tap WILL be hotter, which is
all I said, after you and Steve Farker seemed to say it wouldn't

Well, if you'll review the thread, I believe you'll find that you said
it will be hotter *before* I ever said anything. In fact, I don't
think you'll find any point in this thread where I said it wouldn't be
hotter at the tap.

However, you didn't just say "the water at the tap will be hotter".
You said it would be "too hot" and that the OP could turn down his HWH
to compensate. I think that is where we have a difference of opinion.

Yes, there will be heat loss when the water stands in the pipe, but
even if you were able to insulate against that from happening, that by
itself would not raise the temperature at the tap, it would only allow
the tap to produce hot water quicker, thus saving water.

And yes, there is heat loss as the "new" water is traveling through
the pipe, but the only point I was making is that insulating the pipes
to prevent that heat loss will not raise the temperature at the taps
*enough* that the thermostat can be lowered. As I implied earlier, I
have never measured the temp as it left the HWH and compared it to the
temp as it came out of the tap, but I'm guessing that the heat loss is
so minimal that (1) the user wouldn't even notice it and (2) the
adjustment on the average HWH isn't precise enough to accurately
compensate for it. In other words, it wouldn't be "too hot".

Now, to actually offer something in direct answer to the OP's
question, I have read that if you do nothing else, you should insulate
the first few feet of the hot water pipe as it leaves the HWH. This is
because heat rises and as the vertical section of pipe at the HWH
cools, it can draw heat from the water in the tank, cooling it down,
and causing the tank to cycle more often. Once you get more than few
feet away, the heat draw begins to decrease to a point where it is
negligible.