A Simple Water Conservation Device for New Homes
Steve Grigory, PE
Instant Hot Water - You Will Love It and Save a Bunch of Water Too
We had a hot water recirculation system installed in
our new home - mainly to provide quick hot water at a shower 50 feet from the water
heater. In our old home I never had a hot water shave even when leaving the hot
water running constantly - big water waster too. I figure just the wife and I save
more than 8000 gallons a year by getting instant hot water. That is almost a months
worth of water for us.
The new system is on a timer (see a better solution
in the next paragraph) that starts the little pump running at times we are most likely to
be using hot water and turns it off when we are not using it. We unplug the timer
when we leave town. We have a $10 timer that allows us up to six periods
of on or off and runs on a battery when it is not plugged into the wall. That way we
do not have to reset it when we return from a trip. Just plug it back in. All
this timer stuff is necessary to save energy. As long as the pump is running and you
are not using hot water, the hot water is being cooled as it circulates through the
concrete and reheated back in the water heater.
After some experience with the timer we are planning
to wire the pump to certain lights in the kitchen and bathroom so that the pump will be on
when the lights are on. When building a house we recommend inside switches for the
pump in convenient locations with indicator lights to shown it is on or off. It
turns out that if the pump is off the water never gets hot in the shower farthest
from the water heater. The water saving fixtures restrict water flow so much the hot
water cools off in the concrete slab before it can reach the bathroom. The pump
causes the water to heat up much faster. We think the switches will be much more
convenient and energy efficient than the timer. I wanted a switch system to begin
with but the builder and plumber talked me out of it. No one had done it that way
before!!!
If I decide to take a shower in the middle of the
day and the pump is not running, I just go to the hot water closet and push a
button. I get hot water faster using the pump than I would running the water until
it gets hot. We have those water saving faucets and shower heads that just let water
dribble out so getting hot water is really slow.
Run your own test.
 | Get a 5 gallon bucket, fill it a gallon at a time
and mark the levels.
|
| Go to each sink, tub and shower in the house and
run the hot water tap into the bucket until the water is hot.
|
| Write down the number of gallons used at each
location.
|
| Multiply the number of gallons used at each
location by your estimate of how many times a day the hot water is used at that
location. If you run hot water the whole time you shave, trying to keep the water
hot, you better refigure use for that sink.
|
| Add the number of gallons a day wasted waiting for
the water to get hot.
|
| Multiply by 365. Big Number huh.
|
I think any house over 2000 square feet in the Hill
Country, including San Antonio, should be required to have a hot water recirculation pump
or better yet - several small water heaters spaced around the house instead of one big
one.
BONUS!!
When you build your house talk to the plumber about
where the hot water line is going to run. Ours just happens to run where you put
your feet while sitting on the commode. Every guest we have had has commented on
this nice feature in our house - foot warmer in the bathroom.
Purely accidental I assure you but not such a bad
idea.
05/16/35
