Many of our clients have “recirc” (or recirculation) pumps in their utility rooms or basements attached to a hot water heater.  Some clients have more than one recirc pump, depending on the size of their home and their needs.

The purpose of a recirc pump is to keep hot water circulating throughout the house so when a member of the household turns on the hot water there isn’t a “cold water slug” for 1-4 minutes where the cold water runs continuously until the hot water from the water heater finally makes it to the tap. These homes are often a good size and the hot water heater is located many feet away from the master bath.

The idea is a reasonable one, but often homeowners are not told the downside of these always-on pumps.

Without a timer on the recirc pump it will run 24/7

and at up to 80 watts/hour (or 1,920 watts /day and 57,600 watts/month).  And it will also waste copious amounts of natural gas since it is continually drawing on the hot water heater (usually heated by gas. If your home has an electric hot water heater, we should talk about that too.)   From an energy/cost perspective, the most efficient way to use a recirc pump is to have it run for just a few minutes ONLY before hot water is needed. Any other times it’s left running is wasting energy and costing money.

Net/net, the recirc pump is a “convenience” but one that costs you unnecessarily and inadvertently.  But there are some easy fixes too.

Built-In Timer

If the pump has a built-in timer, use it. It looks like this:

I can’t tell you how many homes I have visited where the pump had a timer but the setting was flipped to “On”, not Timer.  This is insult to injury since the homeowner believes the pump is not running 24/7 but it is.  Simply move the button to Timer and then push the hour ticks to set the pump to only run for say 3 hours in the morning and 3 hours in the evening.  You will still have hot water in the other hours but it will take just a bit longer to arrive.

Add a Timer

Put a separate timer on the pump (if one is not built-in).  There are several ways to do this, I’ll start with the simplest first. 

Option 1: If the recirc pump plugs into an outlet, this is an easy one to control.  You can use a basic mechanical timer

and set the hours to run like above (say 6:30AM to 9:30 AM) and the appropriate 3 hours (or whatever) in the evening. Plug the recirc pump into the timer and your done.  (Don’t forget to change it during Daylight Savings and back again.)

Option 2: Another basic solution, is to use an On/Off remote switch which starts the recirc pump when the remote button to the Smart outlet is pushed.  Again, the wired recirc pump is plugged into a “Smart” outlet like the Etekcity remote wireless control and the On/Off button is on a separate handheld device.

One has to remember to press the Off button to turn off the recirc pump after it has started the hot water flow (about 5 minutes).
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Option 3: If the recirc pump is directly wired to the circuit breaker panel, this becomes a little more work but still worth it.  The recirc pump originally comes as a plug-in unit and an electrician has converted it (and run the wire through metal conduit).  You can have an electrician convert it backto a 110V wire and plug it into a outlet (and use a timer like above) if there is now an outlet near by.

Option 4: A fourth method for controlling the hours for a recirc pump is a bit more sophisticated routine using Amazon’s Alexa as the controller and timer.  It uses an Alexa device like the Echo, a recirc pump with the regular 110V wire and a Smart plug as the On/Off timer mechanism.  This deserves an article all by itself but you can see that here: Using Smart Plugs and Alexa to Control Your Recirc Pump.