5 Hot-Water Recirculation Systems for Homes Without a Return Line (2026)

Please note: Product availability and information are based on our research at time of writing and are subject to change. Always check Amazon for the latest details before purchasing. Reviews remain editorially independent.

Introduction

Where there is no hot-water return pipe, water that has cooled in the hot line has nowhere to go but down the drain when you open the tap and wait for fresh hot water. A recirculation pump can move that cooled water back to the water heater, but a conventional system needs a dedicated return pipe. The systems in this guide are listed by their makers for homes without one: they use the existing cold-water line to carry the cooled water back to the heater. If your problem is that the heater gives no hot water at all, rather than a long wait, start with our guide to a water heater with no hot water.

This is a documentation comparison, not a hands-on test, and it does not rank the five systems. They are ordered by where the pump goes and how it is started, because those two points decide what you need under the sink and what you plug in where. Everything below is taken from the manufacturers’ own manuals, sheets and catalogs, and statements are theirs; where a document is silent we say so instead of guessing. Systems that need a dedicated return line are not covered.

Quick Comparison Table

In the order they are reviewed below, by pump location and control method. “Not stated” means not found in the documents reviewed.

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Full Reviews: Five Systems by Pump Location and Control

The order below follows how each system is installed and controlled, not a ranking: the Grundfos puts its pump at the water heater and runs on a timer, the TacoGenie runs under the sink on a push button, and the APCOM UT1, Autocirc E1 and Autocirc E10 run under the sink on a built-in sensor and timer. Each entry lists what the maker says is included, what you must supply, and what the documents leave open.

1. Grundfos Comfort System 595916

Pump location and control: Pump and 24-hour timer at the water heater outlet, with a thermostatic bypass valve under the sink at the farthest fixture.

The Grundfos Comfort System 595916 (UP15-10SU7P/TLC) splits the job in two. A stainless steel circulator with a timer goes on the water heater’s hot-water outlet, and a thermostatically controlled bypass (comfort) valve goes under the sink at the fixture farthest from the heater; the valve lets the cooled water move from the hot line into the cold line, which returns it to the heater. Grundfos’s leaflet calls it a “Retrofit solution – no return line required,” and its manual says the system is “to be considered where there is no hot-water return line available.” The manual lists the circulator with its 24-hour timer and line cord, the under-sink bypass valve, two valve mounting screws and two 1/2-inch flex hoses in the box; the leaflet adds a 10-foot line cord.

The leaflet lists 25 W at 115 V, a stainless steel pump housing, a maximum liquid temperature of 150°F and a maximum flow of 6.3 gpm, and the manual gives a maximum working pressure of 145 psi and calls the system “maintenance free.” The leaflet states that the system is “Certified to NSF-61 and NSF-372 standards.” The manual warns that after installation “you may find some warm water in the cold water line at the sink where the valve is installed,” and that it will dissipate in a very short time once the cold line is opened. Grundfos’s documents do not state which water heater types the system is intended for (tank-type, tankless or heat pump); the manual mentions gas- or oil-fired heaters only in installation cautions.

2. TacoGenie 008-CT-USK

Pump location and control: Pump under the sink at the most remote fixture, started with a push button; a control board and heat sensor stop it.

The TacoGenie 008-CT-USK is a small pump that attaches to the hot and cold lines in the cabinet under the most remote fixture. It does not run on a schedule: you start it with a push button, and Taco says the TacoGenie’s heat sensor and control board shut the pump off when hot water arrives at the faucet. A wireless remote kit, extra buttons and a motion sensor are optional accessories sold separately. “USK” means under-sink kit, and Taco’s instruction sheet lists a starter button, a set of two 1/2-inch adapter tees and a set of two 1/2-inch stainless steel flex lines as “included with USK models only.” It needs a 110 V outlet under the sink, which you must install if there is none.

Taco’s catalog (12/12/24) says the TacoGenie is “available for use with tankless or standard tank type water heaters,” and Taco’s sizing data lists the 008 model for medium homes: a total pipe length up to 100 feet with a tank-type heater and under 60 feet with a tankless heater (small and medium homes). The catalog lists the product as California Title 24 compliant; the Taco documents we reviewed contain no NSF statement. On first plug-in, the instruction sheet says the pump starts automatically the first time only and runs until a temperature rise is detected, and it warns that running the pump without it being plumbed into water lines may damage it and void the warranty.

3. APCOM UT1

Pump location and control: Pump under the sink at the most distant fixture, run by a built-in aquastat and a mechanical 24-hour timer.

The APCOM UT1 (kit 100306289, from A. O. Smith’s APCOM line) is an under-sink pump that APCOM describes as designed for single-pipe homes with a standard hot water tank or an indirect water heater. APCOM’s instruction sheet lists a pump with mounting bracket, a 10-foot cord and a built-in aquastat, union tailpieces, nuts and gaskets, two 24-inch flex hoses and two 3/8-inch compression tees, so the hoses and tees come in the kit. Its brochure lists a built-in aquastat at 85° to 104°, a mechanical timer, a medium pipe length of 250 feet, and a 0.60 A motor. You plug it into a grounded 115-volt outlet at the sink and set the timer.

APCOM’s instruction sheet is headed “For use with Tank Systems,” and its troubleshooting guide is headed “Not for use with Tankless Water Heaters.” The sheet lists a minimum water pressure of 20 psi, a maximum of 125 psi and a maximum water temperature of 176°F. APCOM says the UT1 “is not an anti-scald unit” and that there “may be some warm water in the cold water line under the sink,” which will disappear in a short time once the cold line is opened. We found no NSF or UL certification statement for the UT1 in the documents reviewed.

4. Goulds/Laing Autocirc E1-BCAFNCTW-01

Pump location and control: Pump under the sink at the most distant fixture, run by a fixed thermostat (on at 85°F, off at 95°F) and a built-in 24-hour timer.

The Goulds/Laing Autocirc E1-BCAFNCTW-01 (part 60A0G6001) is a self-contained under-sink pump: Xylem’s manual says that with an Autocirc “there is no need to build a separate recirculation line,” and that the unit goes under the sink farthest from the water heater. The pump moves the cool water in the hot line into the cold line, and a built-in auto closure device keeps hot and cold water from mixing when it is off. Xylem’s submittal sheet gives the thermostat as “On 85°F Off 95°F,” and the model also has a built-in 24-hour timer. The manual lists the package contents as the pump unit, a fixing bracket, two fixing screws, two plastic anchors and a quick-start guide, and it describes a 6-foot grounded cord and a 115 V / 60 Hz outlet within 6 feet.

Hoses are bought separately. The manual tells you to “purchase two stainless steel flexible hoses (1/2″ — 9/16″) in the length required,” reusing the existing hoses from the stops to the pump; our guides to braided supply lines and angle stop valves cover those parts. Xylem’s catalog says its autocirc circulators “are designed specifically for standard water heaters,” and the submittal sheet reads “Recirc Pump for Standard Water Heaters”; the 2020 manual has no heater-type wording and tankless use is not stated either way for this model. Xylem’s manual says the pumps are certified as a drinking water system component to NSF/ANSI 61, with a 140°F limit in drinking-water systems, and its catalog says the product is CSA certified to NSF/ANSI 372 for lead content. Xylem’s manual says some “lukewarm” water will appear in the cold line at the pump’s sink and will “disappear in a short time (4-5 seconds)” once the cold tap is opened; that is Xylem’s statement, not a promise for every installation.

5. Laing Autocirc E10

Pump location and control: Pump under the sink at the most distant fixture, run by a fixed thermostat (on at 89.6°F, off at 95°F) and a built-in 24-hour timer.

The Laing Autocirc E10 (model E10-BCANCT1W-23, part 6050E7000) uses the same under-sink arrangement as the E1, with an electronically commutated motor. Xylem’s documents label it the “ACT E10”; that is Xylem’s model name, and ACT D’MAND is a separate product line from ACT, Inc. that is not covered here. Xylem’s manual says a built-in sensor turns the pump on when the hot line cools to 89.6°F and off at 95°F, and the pump has a timer. Like the E1, it has a built-in auto closure device (check valve) and no separate under-sink bypass valve. The package includes the pump with a built-in timer, a 6-foot cord and a wall mounting bracket, and the manual lists “two stainless steel flexible hoses (1/2″ x 3/8″) — length as required (sold separately).” Xylem’s brochure gives 60 W and a rating for 203°F at 150 psig.

Xylem’s brochure says the E10 is “Suitable for tankless water heater” and calls it “designed specifically for tankless water heater applications”; the 2016 manual itself has no heater-type wording. The brochure lists the pump as lead-free under California AB 1953 and “NSF certified,” and the catalog says the product is CSA certified to NSF/ANSI 372 for lead content. Xylem’s manual says some “luke warm” water will appear in the cold line at the pump’s sink and will “disappear in a short time (4-5 seconds)” once the cold tap is opened; that is Xylem’s statement, not a promise for every installation.

Buying Guide: What the Documents Say You Need to Decide

Pump at the heater or under the sink

The Grundfos needs work at the water heater’s hot outlet and a grounded 115 V outlet for its pump cord, while the other four need an outlet under the sink and work at the hot and cold stops. Taco’s sheet says you may need more than one TacoGenie if your hot water supply runs in two different directions from the heater. Which location is practical depends on where you have power and access.

Button or schedule

The TacoGenie runs when you press its button (or use an optional remote or motion sensor). The APCOM UT1, Autocirc E1 and Autocirc E10 run from a built-in sensor and timer: the pump starts when its sensor sees the hot line cool and stops when the water warms, and the makers describe the timer as setting the hours the pump may run. The Grundfos system has a 24-hour timer at the heater.

Heater type: tank, tankless or not stated

Check the documented application against your heater, not the other way round. APCOM marks the UT1 for tank systems only. Xylem documents the E1 for standard water heaters and positions the E10 for tankless water heaters. Taco lists both tank-type and tankless. Grundfos states neither, so confirm with Grundfos if that matters to you. Our tankless vs tank water heater guide explains the difference between the two heater types, and your heater maker’s manual may add its own limits.

Autocirc E1 and E10: What Overlaps and What Differs

The E1-BCAFNCTW-01 and the E10-BCANCT1W-23 come from the same maker and share one concept: a self-contained pump under the sink with a fixed thermostat, a 24-hour timer, a built-in check (auto closure) device, no separate under-sink bypass valve and no return line, with the hoses bought separately. The differences are in what Xylem documents. The catalog says the autocirc circulators are “designed specifically for standard water heaters” (the E1), while the E10 brochure says it is “designed specifically for tankless water heater applications.” The E1 manual lists 10 W (and the catalog and submittal sheet 14 W); the E10 documents list 60 W. The E1 thermostat starts the pump at 85°F and the E10 at 89.6°F. The E1 has a 2020 manual naming the model and NSF/ANSI 61 wording; the E10 documents are dated 2016. Suitability of either model outside its documented application, such as the E1 on a tankless heater or the E10 on a tank-type heater, is not stated in the documents reviewed and remains unconfirmed.

Parts that are not in the box

The E1 and E10 do not include the two stainless steel flexible hoses they need, and the Grundfos, TacoGenie and UT1 include hoses or flex lines. Taco, APCOM and Xylem each call for an outlet under the sink, and Grundfos for a grounded 115 V outlet for the pump at the heater. Other parts may be needed where the under-sink risers are hard copper or plastic, as Xylem’s manual notes.

Certifications, as the makers state them

Grundfos’s leaflet says “Certified to NSF-61 and NSF-372 standards.” Xylem’s E1 manual says the pumps are certified as a drinking water system component according to NSF/ANSI 61, its catalog says the products are CSA certified to NSF/ANSI 372 for lead content, and the E10 brochure says “NSF certified.” Taco’s catalog lists California Title 24 compliance and the Taco documents we reviewed show no NSF statement. We found no NSF or UL certification statement for the UT1. These are the manufacturers’ statements, not our checks; read the product label for what applies to the unit you buy.

Warm water in the cold line and scalding

Grundfos, APCOM and Xylem each say some warm water may appear in the cold line at the sink where the valve or pump is installed and that it clears in a short time once the cold tap runs. APCOM says the time varies from home to home, only Xylem gives a figure (4 to 5 seconds), and APCOM adds that the UT1 is not an anti-scald unit. Check your heater setting with our guide to checking and adjusting water heater temperature, and follow your heater maker’s limits.

Warranty Terms and Conditions

Warranty terms differ in start date, claim route and who may claim. The summaries below follow the printed texts; read the document that came with your unit for the full wording.

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Frequently Asked Questions

Q: Do I need a return line for these systems?

No. All five are listed by their makers for homes without a dedicated hot-water return line; they use the existing cold-water line to carry the cooled water back to the heater. Grundfos’s manual says its system is “to be considered where there is no hot-water return line available.”

Q: Will I get warm water from the cold tap?

It may. Grundfos, APCOM and Xylem each say some warm water can appear in the cold line at the sink where the pump or valve is installed and that it clears in a short time once the cold tap is opened. Only Xylem’s documents give a figure (4 to 5 seconds), APCOM says the time varies from home to home, and nothing here promises that duration for every installation. Taco’s documents do not describe it.

Q: Which of these can I use with a tankless water heater?

By the documents: Taco lists tankless and tank-type heaters, and Xylem positions the Autocirc E10 for tankless heaters. APCOM says the UT1 is not for tankless heaters, Xylem documents the E1 for standard water heaters, and Grundfos does not say. Check your heater maker’s own limits too.

Q: Are the Autocirc E1 and E10 the same pump?

No, but they overlap. Both are Xylem under-sink pumps with a fixed thermostat, a timer, a built-in check (auto closure) device and no separate under-sink bypass valve, and both need two flexible hoses bought separately. Xylem documents the E1 for standard water heaters and positions the E10 for tankless heaters (suitability outside those applications is unconfirmed), and the documents list different power (10 W or 14 W for the E1, 60 W for the E10) and different start temperatures.

Q: Do I need an electrical outlet under the sink?

For the TacoGenie, APCOM UT1, Autocirc E1 and Autocirc E10, yes: Taco calls for a 110 V outlet, APCOM a grounded 115 V outlet, and Xylem a 115 V / 60 Hz outlet within 6 feet. The Grundfos pump and timer sit at the water heater instead.

Q: Is the warranty the same for each system?

No. The terms differ in length, start date and claim route (see the warranty section above). Grundfos’s ends no later than 36 months from manufacture, APCOM’s covers the pump for one year from purchase and requires return to the store, and Xylem’s two Autocirc warranty texts conflict and the documents do not say which applies to a given unit.

Conclusion

These five systems answer the same problem in different ways, and the documents, not a ranking, should drive the choice. If you can plug in at the water heater and want a timer, the Grundfos is the one that puts the pump there. If you want to start the pump with a button, the TacoGenie is the one listed for both tank-type and tankless heaters. If you want a thermostat and timer under the sink, the APCOM UT1 is documented for tank systems and comes with hoses and tees, while the Autocirc E1 is documented for standard heaters and the Autocirc E10 is positioned for tankless heaters, with hoses bought separately for both.

Before buying, confirm the heater type, where your outlet is, the seller shown on the listing and the warranty text that ships with the unit. If your problem is not a long wait but no hot water at all, see our no-hot-water guide.

Product details may change. Always check the listing and the manufacturer’s documents for current information.