Demand hot water recirculating systems can save water and energy in some situations. Potential benefits of installing a demand recirculating system during your next new construction or home retrofitting project, include:
How it Works. In a conventional system with a central water heater, any cold water standing in the pipes between the heater and the point-of-use is dumped down the drain as hot water travels from the heater.
In a demand recirculating system, when the system is activated the pump starts recirculating cooled water that's been sitting in the hot water line and sends it back to the water heater through the cold water line. When the water reaches a desired temperature a control turns off the pump. This proccess is similar to turning on the hot water faucet and letting the water run until it gets hot, but instead of the water going down the drain, it is simply returned back to the water heater—saving energy and water.
In an integrated loop system, hot water is re-circulated intermittently. Hot water is returned to the water heater through the cold water pipes. This proccess raises the temperature of the cold water slightly, but it returns to the usual cold temperature in a short time. For more information, visit the National Association of Home Inspectors website at: http://www.nachi.org