Having installed plenty of tankless water heaters, I can tell you firsthand that while they’re incredibly efficient, they sometimes suffer from one common complaint: waiting too long for hot water at distant faucets or showers. That’s where a recirculating pump comes in—it keeps hot water circulating through your pipes, so you get instant hot water at every fixture.
If you’re ready to cut the wait time, I’ll walk you through the best recirculating pumps for tankless water heaters and help you understand what makes each one a great choice.
Top 4 Recirculating Pumps for Tankless Water Heaters
| Recirculating Pump | Max Flow Rate | Power Consumption | Timer/Control Options | Best For |
|---|---|---|---|---|
| Grundfos Comfort System UP15-10SU7P | 6 GPM | 25-87 watts | Built-in Timer and Thermostat | Whole-house use, instant hot water everywhere |
| Taco 006e3 | 10 GPM | 9-65 watts | ECM motor with speed control | Energy-efficient, high flow rate, whole-house |
| Laing LHB08100092 AutoCirc E1 | 5 GPM | 14 watts | Timer and Thermostat | Best for tankless retrofits |
| Watts Premier 500800 | 4.3 GPM | 25 watts | Built-in Timer | Budget-friendly, great for smaller homes |
1. Grundfos Comfort System UP15-10SU7P – Best Overall Recirculating Pump for Tankless Systems
If you want a reliable, all-in-one solution for instant hot water throughout your home, the Grundfos Comfort System UP15-10SU7P is a top choice. This pump works seamlessly with tankless water heaters and is designed for whole-house use.
Key Features:
- Flow Rate: Pumps up to 6 GPM, ideal for most home sizes.
- Built-in Timer & Thermostat: You can schedule the pump to run only when needed, saving energy, and the thermostat prevents overheating the water.
- Comfort Valve: It comes with a comfort valve that can be installed under the sink farthest from the water heater to circulate the water efficiently.
Why It’s Great for Tankless Water Heaters:
- Eliminates Cold Water Wait Time: This pump recirculates water back to the water heater, so when you turn on the faucet, hot water is almost instant.
- Energy Efficiency: With its timer and thermostat, you can set it to run only during peak hours, reducing energy consumption.
- Easy Installation: It’s designed for easy retrofit installations, meaning you can set it up without modifying your plumbing much.
Pros:
- Reliable and durable—built to last with solid components.
- Works quietly, so you won’t hear it running.
- Great for whole-house systems, ensuring hot water at every fixture.
Cons:
- Pricier than budget models.
- Not ideal for homes with extreme water pressure needs.
2. Taco 006e3 – Best Energy-Efficient Recirculating Pump
The Taco 006e3 stands out for its energy efficiency and high flow rate. It’s one of the best options for larger homes or households that use a lot of hot water, all while keeping your energy bills low.
Key Features:
- Flow Rate: Pumps up to 10 GPM, perfect for large homes or systems with high hot water demand.
- ECM Motor: The electronically commutated motor (ECM) automatically adjusts the pump speed based on demand, optimizing energy usage.
- Low Power Consumption: The motor can run between 9 and 65 watts, depending on water usage, making it one of the most efficient pumps on the market.
Why It’s Great for Tankless Water Heaters:
- High Efficiency: The ECM motor ensures you’re only using as much energy as needed at any given time, which is crucial when paired with a tankless water heater.
- Powerful Flow: The 10 GPM flow rate makes this pump ideal for larger homes or homes with multiple bathrooms.
- Durable Build: Taco pumps are known for their reliability and long service life.
Pros:
- Energy-efficient, helping you save on electricity bills.
- High flow rate for homes with high water demands.
- Quiet operation, so you won’t even know it’s running.
Cons:
- Higher upfront cost, but energy savings over time make up for it.
- May require professional installation due to the more complex setup.
3. Laing LHB08100092 AutoCirc E1 – Best for Tankless Water Heater Retrofits
The Laing AutoCirc E1 is specifically designed for tankless water heater retrofits, making it a great choice if you’re upgrading your current system to include a recirculating pump.
Key Features:
- Flow Rate: Pumps up to 5 GPM, enough to handle typical household hot water needs.
- Timer and Thermostat: You can set this pump to run during specific times of day or at certain temperatures, helping to minimize energy use.
- Compact Design: The small size of this pump makes it easy to install in tight spaces, ideal for RVs or smaller homes.
Why It’s Great for Tankless Water Heaters:
- Retrofit-Friendly: This pump is designed to work with existing plumbing systems without the need for extra return lines, making it perfect for retrofitting homes with tankless systems.
- On-Demand Hot Water: It’s designed to deliver hot water quickly while being highly energy-efficient.
- Minimal Installation: It doesn’t require any additional pipes or major modifications, making it a straightforward solution for most homes.
Pros:
- Quick installation, especially in existing setups.
- Works great for point-of-use applications like distant bathrooms or kitchens.
- Built-in controls for easy programming and energy savings.
Cons:
- Lower flow rate compared to higher-end pumps.
- May struggle with larger homes or homes with high water demand.
4. Watts Premier 500800 – Best Budget-Friendly Option
For those looking for a cost-effective solution that still performs well, the Watts Premier 500800 is an excellent choice. It’s affordable, easy to install, and works well for smaller homes.
Key Features:
- Flow Rate: Pumps up to 4.3 GPM, making it suitable for homes with 1-2 bathrooms.
- Built-in Timer: The built-in 24-hour timer lets you control when the pump runs, saving energy during off-peak hours.
- No Return Line Required: It comes with a sensor valve that installs under your farthest faucet, so you don’t need to install a dedicated return line.
Why It’s Great for Tankless Water Heaters:
- Budget-Friendly: For homes that don’t need a high-end pump, this model provides great value without sacrificing performance.
- Simple Setup: Installation is straightforward, and the pump connects directly to your existing plumbing without requiring a dedicated return line.
- Energy-Saving Features: The timer helps to ensure the pump only runs when needed, preventing waste.
Pros:
- Affordable while still delivering reliable performance.
- Easy to install, perfect for DIY enthusiasts.
- Works well for smaller homes or single-level layouts.
Cons:
- Lower flow rate means it’s not ideal for large homes or multiple fixtures running at once.
- Lacks some of the advanced features like thermostatic control found in higher-end models.
Key Factors to Consider When Choosing a Recirculating Pump for Tankless Water Heaters
1. Flow Rate (GPM)
- The GPM (Gallons Per Minute) determines how much water the pump can move. For small homes, 4-6 GPM is usually sufficient. For larger homes or homes with high water usage, aim for 8-10 GPM.
2. Energy Efficiency
- Look for pumps with ECM motors (like the Taco 006e3) or those with timers and thermostats to minimize energy consumption.
3. Installation Type
- Some pumps, like the Watts Premier and Laing AutoCirc, don’t require a dedicated return line, making them easier to retrofit into existing systems.
- If you’re retrofitting your system, look for models that are easy to install with your existing plumbing.
4. Control Options
- Built-in timers and thermostats can save energy by only running the pump during certain hours or when the water temperature drops below a set point.
5. Noise Level
- Some pumps, especially those with higher flow rates, can be noisy. Look for models like the Grundfos or Taco, which are known for their quiet operation.
Pros and Cons of Recirculating Pumps for Tankless Water Heaters
| Pros | Cons |
|---|---|
| Instant hot water at every faucet | Upfront cost for the pump and installation |
| Saves water by reducing the time waiting for hot water | Energy consumption if not set with timers |
| Easy to retrofit into existing systems | Some models require professional installation |
| Reduces wear and tear on the tankless unit | May require periodic maintenance or adjustments |
Conclusion: Which Recirculating Pump Is Right for You?
If you’re looking for the best overall solution that can handle whole-house needs and work efficiently with your tankless system, the Grundfos Comfort System UP15-10SU7P is hard to beat. It’s reliable, efficient, and delivers instant hot water throughout the home.
For energy efficiency, the Taco 006e3 stands out with its advanced ECM motor, offering great performance while keeping your power bills low.
If you’re retrofitting a system and need a simple yet effective solution, the Laing AutoCirc E1 is the way to go, especially for smaller homes.
Finally, if you’re on a budget but still want to eliminate the wait for hot water, the Watts Premier 500800 offers great value and performance at a lower price point.
With any of these pumps, you’ll save water, energy, and time, while ensuring a more enjoyable hot water experience from your tankless system!