Recirculation Systems: Are They Really Worth the Money?
What is a recirculation system?
Sometimes called a circulator pump, it is a pump that periodically circulates water back to the water heater to be reheated. This prevents water in the pipe from cooling off, so it is hot when you turn on the tap or shower. The system is typically set up to circulate the water between the heater and the furthest fixture from it.
What are the parts to a recirculation system?
1). A water heater and pump combined or separate. This can be a tankless water heater with an integrated recirculation pump or a water heater and an external pump. The Rheem RTGH is one of example of a unit with a built-in recirculation pump.
Other models, like the Rinnai RL water heaters, can be programmed to start an external pump during peak water usage times.
2). A recirculation method – 2 options. The first option is a dedicated return line for circulation. That means your home would have three pipes instead of two – cold, hot and recirculation. This is a viable option if it is installed when the plumbing is originally installed or if you have a one-story home and pipes in the basement or crawlspace are easily accessed.
If your home doesn’t have a recirculation line, then a bridge valve will be installed at the furthest fixture that allows the cold-water line to be used as the means of cycling water back to the water heater.
3). A way to control when the circulation pump runs. The two common options are a timer that periodically turns on the recirculation and an aquastat or thermostat that turns on the pump to keep water in the line at the desired temperature.
Many recirculator pumps have a built-in aquastat or timer.
If you’re still wondering what a recirculation system does, here’s a helpful video from This Old House. It shows a tank-style water heater, but the way the system works is the same.
Advantages of Recirculation
Convenience: This is the only proven advantage. You don’t have to wait a minute or two, sometimes longer, for hot water to reach the tap, shower head or clothes washer.
Potential cost savings: Some readers are thinking, “Wait a minute. How does this save money? The unit is running more often, burning fuel, and that is a cost, not a savings.”
That’s exactly right.
If you have a well, the only energy being used during the time it takes for hot water to reach the tap is a little bit of electricity to run the pump. Recirculation technology will cost you money for the convenience it provides.
If you have very expensive metered water (think California or Arizona), then might save more money on your water bill than you’ll spend on gas to fire the water heater during recirculation.
Many sellers encourage recirculation technology in the name of conservancy. The water you save is offset by the fuel you burn.