Green Plumbing Layouts – Plumb Your New Home to Conserve Water & Energy
Faster hot water adds convenience, saves water, and in doing so reduces green house gas
New homes should have efficient green plumbing layouts and systems
Green plumbing layouts are not considered in most new home
construction. Maybe it’s time we took a look at what can be done to optimize
the plumbing system to conserve water and energy.
Since one generally has to wait for hot water, and runs
water down the drain while waiting, both water and water heating energy get
wasted. This waste can be substantially reduced or even eliminated with proper
plumbing layout design.
Long cold hot water pipes make you wait
To get hot water from your water heater you must first
empty all the cooled-off water from the hot water piping. But even then you
still won’t have hot water since the heat gets absorbed into the cold piping
material as it travels to the fixture. To get hot water to the fixture it takes
about 1-1/2 times more water run down the drain than the volume of water
contained in the hot water piping.
Traditionally residential house blueprints do not show how
to route the pipes for the plumbing. The locations of the fixtures, sinks, etc.
are shown, but not how to connect them. This leads to all sorts of plumbing
configurations. The plumbers, often very low paid non-skilled labor, just hook
the pipes up however is easiest. I’ve seen tract homes with identical floor
plans with three or four completely different piping layouts.
When soft copper piping is used the plumber sometimes
leaves a few coils just before a connection so he doesn’t have to take the time
to cut the extra few feet off. Normally when using rigid copper pipe, the
piping is run along joists and makes right angle turns to get to its
destination. This makes the piping runs much longer than if the pipes were sent
directly to their destination.
Low flow fixtures create slow hot water problems
In the days before low-flow fixtures, to get high flow
rates you would use larger pipe. That doesn’t work anymore. Low flow fixtures
limit the flow rate to the point where using larger piping simply means you have
to put more water in the pipe and so it takes even longer to get your hot water.
One common practice is to run a large main pipe through the
house with smaller branch pipes tapping in to the main pipe to get water to the
fixtures. We will call that “branched” plumbing. Another method used is
“looped” plumbing where the pipe goes from the water heater to the nearest
fixture, then from there on to the next fixture and so on.
A relatively new method is to use pex plastic pipe, with a
main run to a manifold and small diameter pex tubing from the manifold to the
various fixtures. This is known as a “Manifold” system. Oddly enough, pex
piping cools off more rapidly than copper piping.
Green plumbing layouts depend upon the floor plan
The most efficient plumbing layout would depend heavily on
the floor plan of the house. Plan your plumbing layout before you begin
construction. Figure out how to plumb the house with the shortest possible pipe
runs especially for heavily used fixtures like the master bath and kitchen.
Keeping the pipe short will reduce the amount of water you must run down the
drain waiting for hot water and thus save you water and energy. It saves you
energy because you end up with less hot water sitting there cooling off in the
pipes after you finish using it.
Insulate the hot water pipes to conserve
Insulate the hot water pipes. Insulating the pipes keeps
them from cooling off as fast, thus the new hot water doesn’t have to give up so
much heat to the piping material when first called for. The hot water doesn’t
loose as much heat energy from the piping when insulation is used. This will
help conserve energy.
Power-assist (demand) hot water systems
Consider a power-assist hot water system. Power assist hot
water distribution systems are better known as hot water demand systems. When
you want hot water you “demand it” by pressing a button. A pump sends the water
very quickly through the piping to the fixture. The pump does not have to pump
the water through a low flow fixture, so high flow rates are possible producing
very short delivery times.
Hot water demand systems can be used with a dedicated
return line which returns the cooled off hot water in the hot water piping back
to the water heater inlet, or the pump can be located at the fixture and use the
cold water pipe as the return. When hot water reaches the pump it shuts off so
no hot water gets in the cold water line.
Because the pumps only run for a few seconds at a time, and
only when hot water is demanded, they use very little energy. Typically they use
less than $2.00 per year in electricity. Since no water gets run down the drain
waiting for hot water it saves a lot of water. A typical family of four can
save up to 14,000 gallons per year.
Saving water and energy
Demand hot water systems are by far the most efficient
systems since they eliminate the wasted water that normally gets run down the
drain. They can also save energy. Many people let the hot water run and do
something else while they wait. When they return to use the hot water, they’ve
been running HOT water down the drain. Heating water is much more expensive
than the cost of the water itself. So with a hot water demand system you can
save a lot of energy too.
When using one of these efficient power-assist systems it’s
best to use “looped” plumbing and place the pump at the end of the line. That
way one pump can serve the entire house.
Manufactures of such systems include Chilipepper Sales,
Metlund Enterprises, and Taco Pump Company. Prices for such systems range from
less than $200 to more than $700.
Go green with your plumbing layout and make it as efficient
as possible since it will be around for a long time to come.
Chilipepper Sales 1380 Greg St., # 221 Sparks Nevada, 89431