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Hot Water Recirculation Systems

A pump rapidly moves water from a water heater to the fixtures

Hot water recirculation device

Innovative hot water recirculation systems deliver hot water to fixtures quickly without waiting for the water to get hot. Rather than relying on low water pressure common in most water lines, recirculating systems use a pump to rapidly move water from a water heater to the fixtures.

In this system, a recirculating pump rapidly pulls hot water from a water heater while simultaneously sending cooled-off water from the hot water lines back to the water heater to be reheated. In addition to having the convenience of hot water on-demand, the system conserves water and can save energy.

Hot water recirculation systems can be activated by the push of a button, or by a thermostat, timer or motion sensor. Systems that use a thermostat or timer automatically turn on the pump whenever water temperature drops below a set-point, or when the timer reaches a setting. These systems ensure that hot water is always available at the faucet without any waiting.

Systems that use a thermostat or timer may use more energy than on/off button or switch operated systems, due to more frequent recirculation cycles and hot water constantly being left in the pipes to cool off.

Hot water recirculation systems generally consist of a pump, an integrated electronic controller, and a zone valve. When the activation button is pushed, or when another type of control turns the system on, 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 closes the zone valve and turns off the pump. It is much like 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. When the hot water faucet is turned on, hot water is readily available.

The system is designed to provide hot water at the most distant fixture and every fixture in series or close to the main line. All cold water fixtures still receive cold water, and the system is designed to not allow hot water to enter cold water lines. Only one pump is necessary to supply hot water to any fixture. Optional wireless remote control units let the user turn on the system from any faucet or fixture in the house.

Energy Efficiency

When controlled manually or automatically, recirculation systems reduce the amount of wasted hot water (e.g., water that goes down the drain while the homeowner waits for the desired temperature). If recirculation systems operate continuously, however, they have the potential to use significantly more energy for pumping and for hot water energy lost from the pipes than they save by reducing hot water waste.

Environmental Performance

Recirculating systems reduce the waste of water while waiting for hot water at faucets.

Quality and Durability

Recirculating systems deliver hot water to faucets quickly, adding convenience for the homeowner.


Hot water recirculation systems are commercially available nationwide through the manufacturer, distributor, plumbing wholesale supply warehouse or at selected retail home stores. Initial cost may prevent some from using recirculating hot water systems. Energy savings will vary depending on the design of the plumbing system, method of control and operation, and homeowner use.

The system is easily installed and costs less than $400.

The pump uses little electricity and saves water in the long run, The amount saved varies on system usage and plumbing design.

No special approval or requirements are needed to install this system into your home or office. Some jurisdictions are offering a rebate on the purchase and installation of a hot water recirculation system.

Not Applicable

System components are pre-wired and assembled as a unit. Installation is a simple matter of connecting the water system between the hot and cold water supply, attaching the push button to the low voltage wire provided, and plugging into a 110 Volt outlet. The whole system can be installed in a few hours and does not require major modifications to the plumbing system. Only simple hand tools, such as an adjustable wrench or screwdriver, are needed.

Warranties range from 1 to 5 years depending on manufacturer and model.

Hot water recirculation systems can be used in any home with standard plumbing. Hot water arrives at fixtures faster than average. Savings in water consumption and energy can be realized; the amount of savings depends on how the system is controlled and how the system is used.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.