Bob F wrote:

"Harry K" wrote in message
news:9d302c20-3ef1-48b4-93e3-

....
Seems an extra expense for no gain. You are paying to dump cold water
back into the heater to be reheated. That has to cost more than the
same water put down the drain. Then having to turn on the pump and
wait comes to the same thing as just turning ont the water and waiting
for it to get hot.

Leavign the pump on would increase the cost as you would be constantly
reheating the same water.


You think it would cost less to buy new water and heat it from near freezing
than to re-heat room temp water? Somehow, I can't agree.


The two are not easily comparable.
With one you are spending energy only when you initially use hot water.
With the other you are constantly spending energy.
Factors involved in making the comparison include:
incoming water temperature, size and length of water lines,
how well insulated they are and whether they are in conditioned
or unconditioned space, how hot you want the water before you
start using it, etc.

Also, if you don't have a separate return loop, your cold water
in the house will always be warm (or hot) unless you run it for
a while before use (like you used to do for hot water).