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Hot water recirculation
wrote:
Jeff Wisnia wrote:
....
The Grundfos pump on a timer with no temp sensing would run a lot more
than that. Running for a mere 2 hours per day, eg 8-9 AM and 9-10 PM,
it might use 50 Wh of electricity plus about 2 kWh for pipe heat losses,
totaling 2.05 kWh/day or 749 kWh/year, ie $75 at 10 cents/kWh. The Taco
system might run for 3 minutes per day, filling half the pipe (only the
hot pipe) at a cost of $36/year, about the same as the manual method,
ignoring trips to the loo or the kitchen without hot water use.
I looked at these recirc pumps before I had replaced a dip tube that
incidentally made a hot water problem moot.
I looked at a "chillipepper" brand. One thing it did was get turned on
via X10 (perhaps with a timer).
If you run the hot down the hot and the warm/hot back up the cold for
30-60 seconds, when you turn on the tap, you get warm to hot water.
This makes my sleepy face happy.
Now, there's warm water backed into the cool a little bit with this.
But frankly, I'm washing my face, dealing with the AM. By the time
I get to the bathroom, the hot water should be actually hot, so the
device is now off. If I hit the cold water to get warm, as the cold
pipe empties of lukewarm water to become cold (lets say 15 seconds of
use, it's filled with cold).
Bottom line, the device turns on just enough to get hot water to the
tap with about 30 seconds of advance warning.
If you do stuff and use NO cold water, then yeah, you leave some
warm water in the cold pipe. Most of the time, people mix.
They also advertise that they draw the water fast enough to turn on
a tankless waterheater.
So you're "6 times a day" means that you run this sucker 3-5 minutes a
day at a few pump watts.
No special return pipe (which would be a pain in my existing bathrooms).
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