How much does a hot water recirculating pump cost to run?

What it costs to buy or replace

HomeGuide's national range to replace an existing recirculating pump is $150 to $680, as of August 2025^[6]. That covers swapping a pump on a system that is already plumbed.

A new system costs more, and the spread is wide:

• Crossover (comfort valve) retrofit. A pump at the water heater and a valve under the furthest sink. No new pipe runs, so labor is usually limited. You may need a 120 V outlet near the heater.
• Under-sink on-demand pump. Mounted at the furthest fixture. It needs an outlet under that sink and sometimes low-voltage wiring for buttons.
• Dedicated return line. A new pipe from the far end of the loop back to the heater. Opening walls, ceilings or crawlspaces drives the price.
• Tankless with a built-in pump. The pump comes with the heater, but you still need a return line or crossover valve. See recirculation with a tankless water heater.

We could not find a national installed-cost survey for new recirculation systems that we trust enough to quote. Ask for a written quote that names the pump, the control type, the return path, and any electrical work.

What the pump's electricity costs

The pump motor itself uses little power. The Grundfos Comfort System pump is rated at 25 W^[4]. NREL's 2025 training uses an 80 W pump in its worked example^[5]. We use both below, at EIA's July 2026 U.S. average residential price of 18.31 cents per kWh^[1].

The formula: watts x hours per day x 365 / 1,000 = kWh per year. Then kWh x price = dollars per year.

Control	Pump	Hours per day	kWh per year	Cost per year
Continuous	25 W	24	219	about $40
Continuous	80 W	24	701	about $128
Timer (2 hours morning, 2 afternoon)	25 W	4	36.5	about $7
On-demand, 6 uses a day, 5 minutes each	80 W	0.5	14.6	about $3

How we got these (our arithmetic):

• 25 W x 24 h x 365 = 219,000 Wh, or 219 kWh. 219 x $0.1831 = $40.10.
• 80 W x 24 h x 365 = 700,800 Wh, or 700.8 kWh. 700.8 x $0.1831 = $128.32.
• 25 W x 4 h x 365 = 36,500 Wh, or 36.5 kWh. 36.5 x $0.1831 = $6.68. The 4-hour schedule is the typical timer pattern NREL describes^[5].
• 80 W x 0.5 h x 365 = 14,600 Wh, or 14.6 kWh. 14.6 x $0.1831 = $2.67. The 5-minute run is the maximum per request on Rinnai's on-demand controls^[8]; real runs are often shorter.

Your rate may be much higher or lower than the national average. Swap in the price per kWh from your bill.

The bigger cost: heat lost from the pipes

The pump is the cheap part. When hot water sits in or moves through a loop, it loses heat through the pipe walls, and the water heater has to make it up. ENERGY STAR warns that continuously running systems can use more energy, through pumping and pipe heat loss, than they save by cutting hot water waste^[7].

NREL's 2025 training cites energy savings of 800 to 4,000 kWh, or 100 to 226 therms, per year from on-demand recirculation, depending on the baseline system and how it is run^[5]. Converted to dollars (our arithmetic):

• Natural gas. EIA's 2025 average residential price was $15.34 per thousand cubic feet^[2]. At EIA's heat content of 1,036 Btu per cubic foot^[3], a thousand cubic feet holds about 10.36 therms, so gas cost about $1.48 per therm. 100 to 226 therms x $1.48 = about $148 to $335 a year.
• Electricity. 800 to 4,000 kWh x $0.1831 = about $146 to $732 a year.

These are savings figures from field studies, not a bill you will see. They show that the control and the loop's heat loss matter far more than the pump's own wattage.

Ways to keep operating cost down

• Use an on-demand control. It runs the pump only when someone wants hot water^[5][7].
• Insulate the loop. NREL recommends at least R-3 on recirculation piping^[5].
• Use the economy setting if your heater has one. Rinnai's guide shows longer pump-off intervals in Economy mode than in Comfort mode^[8].
• Skip continuous mode. NREL says a continuously operating system "is never recommended"^[5].

Water savings

NREL's training cites water savings of 3,600 to 12,000 gallons a year for on-demand systems, depending on configuration and use^[5]. Grundfos claims up to 12,000 gallons a year in a typical household for its Comfort System^[4]. Check your water and sewer rates to put a dollar value on it.

When to call a pro

• Installing a new pump, crossover valve or return line: plumbing work that may need a permit.
• Adding an outlet or low-voltage wiring for the pump or buttons: a licensed electrician.
• A pump that never shuts off, or a gas or electric bill that jumped after recirculation was added.
• Pairing a pump with a tankless or heat pump water heater, so the controls match the maker's settings.