Is a Hot Water Recirculating Pump Energy Efficient?

A hot water recirculating pump works by circulating or pumping substances such as slurries, gases or liquids in a loop or closed circuit. They are most commonly used for circulating water in a hydronic heating or cooling system. With gravity providing additional help, moving of water around closed circuits will not expend a lot of energy.   

For example, when water is initially pumped upwards, it will circulate around a system and eventually return to its original position; pump power is only required to counteract the inertia or drag in pipes to propel the water forward efficiently. This process is repeated over and over again.

Because circulating pumps run on little energy, circulating pumps designed for home usage are small enough to fit alongside plumbing systems.

Pump Structure

Circulating pumps used in the home are basically centrifugal pumps that are electrically powered and quite compact; their sole purpose is to produce hot water on demand.  Without them, users will not only have to wait for water to heat, they will also witness a lot of water running down the drain each time they turn on the hot water tap. The three main components of a circulating pump are:

  • Support bearings
  • Pump impeller
  • Motor rotor

The impeller is powered by an electric motor. It then forces the water forward or upward. An impeller is like a turbine since it is a wheel with a series of angled blades. The impeller rotates extremely fast; it pushes water out and compresses it. The motor is sealed in a waterproof casing; this is connected to the impeller. Home circulating pumps are typically small enough to be mounted alongside plumbing systems, industrial type pumps have large designs and their motors are usually fixed on separate locations away from the piping system.

Kinds of Home Circulating Pumps

There are different kinds of home circulating pumps. Full time circulating pumps work round the clock and consume a lot of energy.  Hot water is constantly pumped by the water heater even if there is no demand for such. This type of system is expensive to maintain and can put undue pressure on the pump and heater.

Timer controlled pumps turn on and off in intervals. Users can program their pumps to work only when the demand for hot water is high such as mornings and early evenings. The downside to this design is when you need hot water at a time the pump is not supposed to operate; you will have to wait for heated water to flow out of your tap.

Temperature controlled pumps on the other hand turns on and off depending on the temperature of the water in the pipes. If the water temperature falls below a prescribed level, the pump turns on to circulate water in the piping line until the desired level is achieved.

Hot water demand system pumps are by far the most energy-efficient and cost-efficient. Powered by a remote button or motion sensor, they work only when you need hot water. On average, they cost only $1 a year to operate.