A hot water recirculation system is a plumbing system that moves hot water to fixtures continuously. Recirculation systems reduce the amount of water that goes down the drain while you wait for the water to heat up.
Circulating systems:


Conserve water. According to statistics from the U.S. Department of Energy and the U.S. Census Bureau, between 400 billion and 1.3 trillion gallons of water (or close to 2 million Olympic-sized swimming pools) are wasted nationally by households per year while waiting for water to heat up.

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

• Limit municipal energy waste. The DOE estimates that 800 to 1,600 kilowatt-hours per year are used to treat and pump the water to households that will eventually be wasted while the occupant waits for tap water to warm to the desired temperature.


Source: Hot Water Recirculation Systems – InterNACHI