Systems to help conserve water can also waste energy

Published 3:05 pm Wednesday, July 14, 2010

While much of our time is spent recommending what you can do to your home to improve its value, and to make it a more enjoyable place to live, we sometimes forget to make you aware of those products or systems that aren’t cost-effective.

There are many types of hot-water recirculating systems. What they all do well is keep the hot water lines in your home filled with — you guessed it — hot water.

The result being that you don’t have to wait several minutes for the hot water to arrive at the faucet or shower when you turn on the valve.

Thus, thousands of gallons of water are prevented from being run down the drain and, thus, lost forever.

The other side of the coin is that the energy used for some of these systems can be wasteful.

There are two basic types of systems: gravity fed and pumped.

With a natural “gravity-fed system” water travels into a pipe at the top of the water heater (as usual), but instead of heading for the nearest water fixture, the pipe travels straight up until it reaches the attic.

Once in the attic, the pipe angles about 90 degrees from vertical to horizontal, but angles slightly upward of horizontal as it travels across the house and away from the water heater.

At the other end of the attic, the pipe travels downward within a wall and then under the house and back to the water heater. From this “return pipe” fixtures, pick up the heated water.

Thus, naturally recirculated hot water is achieved and used. It all works because physics teaches us that heat moves toward cold.

The hot water in the water heater travels toward the cold water in the pipe in the attic.

An endless siphon begins and this naturally occurring “hot water chasing cold” phenomenon allows water to circulate in the looped pipe continuously without a pump (or any other mechanical control), thus providing a ready source of hot water to all fixtures in the home. Instant hot water: What a concept.

Although water does not have to run for several minutes to warm up — conserving water — we do not recommend this system because it cannot be controlled. Yes, the good thing is that the system runs continuously. But that’s also the bad thing — it runs at all hours whether you need it or not.

This means that your water heater will run more often to keep the water warm and therefore waste precious heating energy. So, what’s a person to do?

Pump it. And turn the pump on and off when water waste isn’t an issue. So when is water waste not an issue? The answer to the question is one that only you can answer by asking yourself another question: When is the water in your home used most frequently?

When water is being used, recirculating hot water is not being wasted. The answer: With a pump, a recirculating system can be managed so that the system only runs when needed.

A plumbing contractor we know who had originally installed a gravity system in his own home later added a pump on a timer so he could stop the gravity system from operating.

He told us that the gravity system was costing a fortune to operate.

For tips from James and Morris Carey, go to www.onthehouse.com or call the listener hot line, 800-737-2474, ext. 59. The Careys are also on KRKO (1380-AM) from 6 to 10 a.m. every Saturday.