Recirculation Pumps: What You Need to Know

Mar 19, 2021

Test your tankless IQ

  1. A tankless water heater provides endless hot water.  Yes or no?
  2. A tankless water heater provides instant hot water.  Yes or no?

If you answered yes to question number one, you are correct: Tankless water heaters do provide endless hot water which makes it a great investment for your home.  

However, if you answered yes to number two, please keep reading. 

Tankless water heaters do not provide instant hot water despite rumors to the contrary.  In just five minutes on Google, we found several websites that suggested tankless water heaters do deliver instant hot water.  The truth is, with whole-house tankless systems, the hot water is still a long way from many taps and takes a long time for the water to warm up.

Waiting for water to warm up before using it is literally sending your money down the drain. We did a little fact-checking and found that according to the Natural Resources Defense Council (NRDC), around 10 percent of all water drawn for showering in an average single-family home is waiting for hot water to arrive. 

Put another way, over 10,000 to 15,000 gallons of water are wasted per year in the average home just waiting for water to warm up! The cost of this wasted water is enormous. Not only is your water bill higher (and most of us in the San Diego area have expensive metered water) but it drains our precious water supply. Not to mention the time wasted waiting for warm water.

The Solution: A Recirculation Pump

A recirculation pump keeps heated water in the tap and instantly available at the sink or shower. The pump periodically circulates water back to the water heater to be reheated. This prevents water in the pipe from cooling off so that it is hot when you turn on the tap or shower. The recirculation system is usually set up to circulate water between the heater and the fixture furthest from it.

A recirculation system includes: 

  1.  A water heater and pump either separate or combined (like your all-in-one printer). We recommend keeping the water heater and pump separate.
  1.   A recirculation method. Some houses (about 10%) have a dedicated recirculation line (also known as a return line). Your home would have three pipes instead of two – cold, hot and recirculation. If your home doesn’t have a recirculation line, then a bridge valve can be installed at the furthest fixture which allows the cold water line to be used to cycle water back to the water heater.
  2. A way to control when the pump runs. Many pumps have built-in timers or thermostats that keep water in the line at the desired temperature.

This information can be a little confusing so we’ve included a link to a “This Old House” video that explains the process visually. They work with a traditional tank heater, but the process is the same.

How to Get Hot Water with a Recirculation Pump 

There you have it – endless hot water via a tankless water heater and instant hot water via recirculation. Recirculation systems do have an upfront cost, but you’ll save time, money and water from going down the drain! Recirculation systems can be self-installed or installed by us.