Posted by Walter R. on June 13, 2004, 9:16 pm
A friend of mine is tired of waiting for hot water and wants to install a
instant hot water system in his house, for a few hundred bucks.
At first I thought this is impossible without installing a separate pipe,
circulating the hot water to the heater in a loop. But, Google tells me that
these new systems use a recirculating pump and a thermostatic bypass valve
at the farthermost hot water outlet.
When the water at the hotwater faucet cools to 85 degrees, the pump
activates and the valve pushes the previously hot (but now cooler) water
into the cold water pipe.
This system claims enormous savings of water that would otherwise go do the
drain (until the hot water arrives at the faucet). It seems to me that the
system saves water at the expense of constantly heating all the water in the
hot water pipes: A great waste of energy.
An instant hot water system makes sense in an apartment building or hotel,
but not in a home.
Furthermore, this system would constantly push 85 degree water into the cold
water line. Yuk!
Has anyone tried this system?
http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?prod_id 165
8&cm_ven=hd_goog&cm_cat=Search&cm_ite&-6-11-instant_hot_water-PR-20-161658
--
Walter
The Happy Iconoclast www.rationality.net
-
Posted by RedFox on June 14, 2004, 1:47 am
> A friend of mine is tired of waiting for hot water and wants to install a
> instant hot water system in his house, for a few hundred bucks.
> At first I thought this is impossible without installing a separate pipe,
> circulating the hot water to the heater in a loop. But, Google tells me
that
> these new systems use a recirculating pump and a thermostatic bypass valve
> at the farthermost hot water outlet.
> When the water at the hotwater faucet cools to 85 degrees, the pump
> activates and the valve pushes the previously hot (but now cooler) water
> into the cold water pipe.
> This system claims enormous savings of water that would otherwise go do
the
> drain (until the hot water arrives at the faucet). It seems to me that the
> system saves water at the expense of constantly heating all the water in
the
> hot water pipes: A great waste of energy.
> An instant hot water system makes sense in an apartment building or hotel,
> but not in a home.
> Furthermore, this system would constantly push 85 degree water into the
cold
> water line. Yuk!
> Has anyone tried this system?
http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?prod_id 165
8&cm_ven=hd_goog&cm_cat=Search&cm_ite&-6-11-instant_hot_water-PR-20-161658
> --
> Walter
> The Happy Iconoclast www.rationality.net
Hello Walter,
My understanding of instant hot water systems is that there is a single
heater unit
close to the sink where the water is used. It could be gas or electric and
involves no hot water storage. A recirculating hot water system is
different. In California, the building code now requires a recirculating
loop in the hot water system if the sink is more that 10 feet from the water
heater. The purpose of this is to save water.
The instant hot water system saves the energy that the hot water tank would
lose over the 24 hour period plus the energy that the recirculating water
loop would lose. These are fairly common even in homes. A heavily insulated
tank and recirculating pipes would reduce substantially the amount of energy
loss.
HTH
RF
Posted by Philip Lewis on June 14, 2004, 10:04 am
>> This system claims enormous savings of water that would otherwise
>> go do the drain (until the hot water arrives at the faucet). It
except when folks run the "hot" cold water till it gets cold. ;)
As for me, i try to run the "cold" hot water into a bottle and use it
to water plants, water for the cats, etc...
it's an imperfect stystem. (i don't think my wife does the same) but a
few drops here and there have to help some.
>In California, the building code now requires a recirculating loop in
>the hot water system if the sink is more that 10 feet from the water
even on electric water heaters? which do they want to save, water or
power? ;) do you know if they require insulation on all hot/cold water
pipes? I think *that* would be a bit more useful.
If the circ pump pushed water back into the hot tank it wouldn't be so
bad.
--
be safe.
flip
Ich habe keine Ahnung was das bedeutet, oder vielleicht doch?
Remove origin of the word spam from address to reply (leave "+")
Posted by Jim on June 14, 2004, 11:47 pm
> >> This system claims enormous savings of water that would otherwise
> >> go do the drain (until the hot water arrives at the faucet). It
>
> except when folks run the "hot" cold water till it gets cold. ;)
>
>snipalot<
In my last house, I had a looooonnnnng run from the heater to the
kitchen.
I installed a 2.5 gallon water heater under the sink, tapped it to the
cold water line, and fed it to the hot water. Worked like a champ. I
suspect I didn't save much electricity. Since it was a tank, it
always idled at the hot water temp. BUT, I didn't have to wait a long
time, and run several gallons of water, each time I wanted hot water.
If it didn't save electricity, at least it saved water and my
sanity...one of which is worth something.
I've spent some time wondering what system is best. It would depend
on the situation. If, for one extreme example, you have a
stereotypical church: no water use all week until sudenly on Sunday
morning. A tank heater isn't a good idea, since it's using energy
idling all week long. Get a tankless heater. Gas is probably
better,since electric would take one heck of a lot of current,
although not for long. If you have lots of people in the family,
drawing water frequently but intermittently, maybe a loop system is
better. That way the frequent wast of water/energy getting hot water
at the tap won't happen. But a loop system had better have pipes
extremely well insulated, or you'll be heating mother earth with your
heater and that is a losing proposition.
A tank's major benefit is low purchase and installation cost by
comparison with about anything else. That's why it is standard--it
saves the builder money. Heck, they won't even insulate the hot water
pipes in the ground. Idiots...
But in general, it may not be a bad compromise.
I like to run the pre-heat water into something and use it for plants.
The BEST is a solar source. ONly takes a small amount of electricity
to get the heat. A couple hundred gallons in the tank is sufficient
most times.
The system described at the beginning of the thread would save water,
but I suspect could use tremendous amounts of energy, unless very
carefully planned and insulated.
Posted by twillmon on June 15, 2004, 10:46 am
My plan, for my under-construction house, is to use a centrally-located
tankless demand gas water heater with short pipe runs to kitchen and bath.
Pipe can be small diameter (3/8" PEX), minimizing volume discharged waiting
for hot to arrive. Since I use harvested rainwater, I expect no clogging
from mineral deposits.
Tom Willmon
Mountainair, (mid) New Mexico, USA
Net-Tamer V 1.12.0 - Registered
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> instant hot water system in his house, for a few hundred bucks.
> At first I thought this is impossible without installing a separate pipe,
> circulating the hot water to the heater in a loop. But, Google tells me
that
> these new systems use a recirculating pump and a thermostatic bypass valve
> at the farthermost hot water outlet.
> When the water at the hotwater faucet cools to 85 degrees, the pump
> activates and the valve pushes the previously hot (but now cooler) water
> into the cold water pipe.
> This system claims enormous savings of water that would otherwise go do
the
> drain (until the hot water arrives at the faucet). It seems to me that the
> system saves water at the expense of constantly heating all the water in
the
> hot water pipes: A great waste of energy.
> An instant hot water system makes sense in an apartment building or hotel,
> but not in a home.
> Furthermore, this system would constantly push 85 degree water into the
cold
> water line. Yuk!
> Has anyone tried this system?