On Feb 16, 5:59*am, "Robert Green" wrote:
"Malcom "Mal" Reynolds" wrote in ...





In article ,
*"Robert Green" wrote:

"RBM" wrote in message
...
On 2/14/2012 7:25 PM, mcp6453 wrote:
The latest episode of "Ask This Old House" showed Rich Trethewey
installing a Taco D'Mand hot water recirculating pump.

http://goo.gl/lq4aw

As usual, the show doesn't give enough information, so it's hard to
say
whether they used the 006 or the 008. In any case, the pumps are
about
$400.

What do you think about these units? Are there cheaper ones? I was
never
in favor of them until I saw that you press a button when you're
ready
to use hot water.

My kitchen is a long way from my hot water heater. This device would
be
very handy unless it causes diseases or something.

The savings estimate seems high and unrealistic to me. I wonder if
they
use the same formula as the EPA did in calculating the Chevy Volt MPG
@
230??

Could be. *I don't see how pushing a button when you enter a bathroom is
much different than turning on the hot water tap. *Factor in the cost of
the
pump, the cost of installation, the cost of operation (electricity) and
the
cost of maintenance and it doesn't seem terribly efficient to me, at
least
at the rate I pay for water v. electricity.

--
Bobby G.

don't confuse efficient with efficacious

Actually, now that I think about it, having to push a button to call for hot
water is an extra step. *If you just turn on the tap when you enter the
room, you're done. *No button pushing, no mechanical pump to wear out or
consume electricity. *The tap's turned on already. *As someone else noted,
the "idling" heat of a pump loop helps heat the house in winter, and that
make it harder to calculate its true benefit. *I still don't know what the
real numbers are concerning lifetime operating costs. *I suppose it comes
down to how many seconds you're willing to wait to have hot water, how long
the run is to the water heater, how much clanging the pipe make at 3AM when
you're washing your hands, etc. *I can't really see it saving any money..
They must do something because so many people install them.

What they do and why people install them is they
can eliminate waiting for hot water to arrive at
a point-of-use that's a long distance from a water
heater. It's a solution to a large house where the
water heater is in the basement at one end and
you have a bathroom on the second floor at the
other end.

I agree that any cost savings in energy and water
are likely to be small and could easily be exceeded
by the cost of the pump, installation, etc.