A hot water recirculation system is a plumbing system that moves hot water to fixtures and circulates the cooled water back to your water heater for reheating. This method of hot water recirculation provides instant hot water for the consumer (not requiring the consumer to waste water down the drain waiting for the water to “run hot”.
dedicated loop: A connection to the hot water supply pipe (at each fixture or near the end of the plumbing run), connects a separate or “dedicated” pipe specifically used to carry the cooled water back to the water heater for reheating. A dedicated loop is normally only installed during the initial new construction of a building (because once walls and floors are closed off, adding an additional plumbing line is very difficult).
integrated loop: This system is typically used on existing buildings and provides a similar function to the “dedicated loop” with the exception that instead of adding an additional plumbing line, it uses existing cold water lines to return the cooled water back to the water heater for reheating.
Hot water recirculation systems are most commonly activated by either a timer or push button. Systems that use a timer or push button turn a pump when activated. These systems require electricity to operate and therefore make installation more difficult.
Perhaps the best hot water recirculating system is one that is thermal convection powered, has a temperature controlled by-pass valve under the farthest fixture sink and required no electricity to operate (which makes DIY installation easy and fast). There is no water waste with this type of system, and it also minimizes energy waste since it only reticulates when the hot water at your faucet cools below your desired temperature.
Do they really save energy and water?
Regardless of whether they are controlled manually or automatically, recirculation systems reduce the amount of water that goes down the drain while the homeowner waits for the desired temperature. This fact allows for the following three advantages over conventional water distribution systems:
They save time. Recirculating systems deliver hot water to faucets quickly, adding convenience for the homeowner.
They 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.
They 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.
Some jurisdictions, particularly in areas where water is scarce, offer rebates on the purchase and installation of hot water recirculation systems. The cities of Santa Fe and Albuquerque, New Mexico, for instance, offer a $100 rebate for homeowners who purchase a hot water recirculation system. The city of Scottsdale, Arizona, offers up to $200 for residential property owners who install theses systems.
Availability and Energy Savings
Hot water recirculation systems are available nationwide from manufacturers, distributors, plumbing wholesale supply warehouses, and at selected retail home stores. The initial cost of dedicated systems may prevent some homeowners from installing these systems, as they require a professional plumber and the purchase and installation a large amount of piping. Integrated systems, by contrast, are often a D.I.Y. solution. Energy savings will vary, depending on the design of the plumbing system, method of control and operation, and homeowner use.
In summary, hot water recirculation systems are innovative plumbing systems that can save water, save energy and time.
Install a temperature controlled hot water recirculation valve, which provides instant hot water (so water is not wasted down the drain waiting for water to run hot at your faucet or shower). This simple DIY installation can save an average household up to 17,000 gallons per year. It also saves energy costs and can prevent pipe freezing.