What is a recirc pump? A recirc pump is short for recirculating pump, a pump normally used in large residential plumbing layouts where it would take much too long to get hot water by just running the faucet.
Traditionally, the hot water piping had a pipe connected from the last fixture on the main hot water run back to the water heater with a recirc pump at the far end of the dedicated hot water return line.
The nice things about hot water recirc systems are the instant hot water available at the fixtures, and you save a lot of water that would otherwise be run down the drain.
The downside is that the system is a Huge waster of energy. Keeping the hot water piping full of hot water requires both pumping energy, and it requires that the water heater fires more often to keep replacing the heat being lost from the piping system.
A residential plumbing layout is like a big car radiator. It continually cools off the hot water being re-circulated by the recirc pump.
The amount of wasted energy can be reduced by reducing the amount of time the recirc pump runs. It could be turned off late at night, and then back on early in the morning. Perhaps if no one is home during the day it could be turned off as well. However, it’s an inconvenience if you happen to want hot water when the system isn’t operating, and it’s not always easy to predict when you might need hot water.
In these unexpected hot water usages one ends up running precious potable water down the drain. In large homes with long pipe runs and large pipe diameters that can be a whole lot of water and a whole lot of time waiting for it.
Enter the hot water demand system – A greener way to save water!
A more recent innovation in the residential hot water distribution arena is the hot water demand system which provides you with quick hot water without running water down the drain. With this type of recirc system you push a button when you want hot water, a pump comes on pumping the hot water to the fixture at high speed, and when the hot water reaches the pump it shuts off.
Most recirc systems won’t work with most tankless water heaters since they do not produce enough flow to turn on the water heater. Most demand systems will turn on tankless water heaters and are compatible with them. This is nice since tankless water heaters typically increase the wait time for hot water by 10 to 20 seconds.
You have instant hot water when you turn on the tap, you didn’t have to wait as long as if you had run the faucet at full blast, and you didn’t run any water down the drain while you waited.
If you want your hot water during some time interval, say from 8:00 am to 9:00 am, you can simply tell the demand system to turn on every 10 or 15 minutes. If the hot water has cooled off the demand system will turn on and start pumping again. If the water is still hot the demand system won’t do anything.
You always have the option of pressing a button at any time and thus you never have to waste any water. Demand system pumps are very cheap to operate, typically using less than $1.00 worth of electricity per year. Some models are available for less than $200.
Be green and convert your hot water recirc pump into a hot water demand system and save energy, and money, as well as time and water!