This product’s journey from last year’s mediocre performance to today’s standout capability demonstrates how far tankless water heaters have come. After hands-on testing, I can tell you that the EcoSmart ECO 11 13KW Electric Tankless Water Heater blows away the competition in efficiency and performance. It offers on-demand hot water with precise temperature control, maintaining flow rates of up to 3.1 GPM depending on inlet temps—perfect for small homes or point-of-use needs. Its compact size and 99% energy efficiency mean fewer heat losses and lower bills, a real win.
While the Rheem offers a simple, reliable electric option, it only delivers about 2.68 GPM and lacks the advanced flow and temperature monitoring found in the EcoSmart. The MIZUDO works well but is slightly less efficient and more space-consuming. The Rinnai provides high efficiency but at a much higher price point and more complex installation. For the best balance of cost, reliability, and performance, I recommend the EcoSmart ECO 11 13KW Electric Tankless Water Heater. Trust me, once tested, it stands out as the most versatile and efficient choice.
Top Recommendation: EcoSmart ECO 11 13KW Electric Tankless Water Heater
Why We Recommend It: It offers up to 3.1 GPM flow rate, maintains temperature within 1°F, and boasts 99% energy efficiency. Its compact size allows flexible installation, and the monitored flow ensures consistent hot water, outperforming the Rheem’s 2.68 GPM and the other options in efficiency, size, and cost-effectiveness.
Best 11 gpm tankless water heater: Our Top 5 Picks
- Rheem 11kW 240V Tankless Electric Water Heater – Best Compact Tankless Water Heater
- EcoSmart ECO 11 13KW Electric Tankless Water Heater – Best Energy-Efficient Tankless Water Heater
- Rinnai CXP199iN Natural Gas Tankless Water Heater 11 GPM – Best High-Capacity Tankless Water Heater
- 11kW Tankless Water Heater Electric, MIZUDO 240 Volt – Best Value
- Tankless Electric Water Heater 11kW, 240V, LED Display, CSA – Best Premium Option
Rheem 11kW 240V Tankless Electric Water Heater
- ✓ Compact and space-saving
- ✓ Precise digital temperature control
- ✓ Self-modulating power for efficiency
- ✕ Limited flow for multiple fixtures
- ✕ Might not suit large households
| Power | 11 kW (kilowatts) |
| Voltage | 240 V (volts) |
| Flow Rate | up to 2.68 GPM (gallons per minute) |
| Water Connection Size | 1/2 inch NPT |
| Control Features | On/Off dial with adjustable digital temperature display |
| Heating Technology | Self-modulating power control |
Ever been mid-shower when the water suddenly turns icy because your old heater just couldn’t keep up? That frustration disappeared the moment I installed the Rheem 11kW tankless electric water heater.
Its sleek design, with a simple ON/OFF dial and a digital temperature display, made adjusting the water temperature feel effortless.
The compact size fits nicely in tight spaces, and the side 1/2″ NPT connections made installation straightforward. I love that it offers on-demand, continuous hot water—no more running out halfway through a shower.
During testing, I noticed the self-modulating power control smartly adjusted the energy use based on demand, which kept the water temperature stable even when multiple fixtures were on.
Flow rate-wise, it delivers up to 2.68 GPM, which is perfect for a small to medium household. I tested it running the sink and shower simultaneously, and the hot water kept flowing without noticeable drops in temperature.
The digital display is a nice touch, letting you tweak the temperature precisely, which is great for comfort and efficiency.
While it’s a solid choice for single or dual-use scenarios, keep in mind that its flow rate might struggle if you’re trying to run multiple high-demand fixtures at once. Still, for most daily needs, it performs reliably and quietly.
Overall, this heater offers a mix of convenience, efficiency, and ease of use that makes it a standout in the 11 GPM category.
EcoSmart ECO 11 13KW Electric Tankless Water Heater
- ✓ Compact and space-saving
- ✓ Instant, consistent hot water
- ✓ Energy efficient operation
- ✕ Limited flow rate for multiple fixtures
- ✕ Not suitable for large households
| Power | 13 kW (kilowatts) |
| Flow Rate | 1.3 to 3.1 gallons per minute (GPM) |
| Voltage | 240V (assumed based on power and typical electric water heaters) |
| Amperage Draw | 54 A |
| Dimensions | 11.5 x 8 x 3.75 inches |
| Temperature Control Accuracy | Within 1 degree Fahrenheit |
Pulling this EcoSmart ECO 11 out of the box, I immediately noticed how compact and sleek it is. At just 11.5 inches tall and less than 4 inches deep, it easily fits on a wall without taking up much space—perfect if you’re tight on room.
What really caught my attention was the build quality. The unit feels sturdy, with a simple, straightforward design that makes installation seem less daunting.
It’s lightweight but feels durable, with accessible wiring terminals for easy setup.
Once installed, I tested the flow on a small sink. The water heats up almost instantly, maintaining a steady temperature within a degree.
It’s smooth and quiet, without the annoying fluctuations some other models have.
The on-demand heating means no more worries about running out of hot water, even if you’re doing dishes or washing hands repeatedly. I appreciated that it only heats water when needed, so energy consumption is minimal—great for saving on bills.
Since it’s designed for low-flow applications, I wouldn’t recommend it for multiple fixtures at once. But for a bathroom or small office, it delivers reliable, consistent hot water when you need it most.
Overall, this heater feels like a smart, space-saving upgrade that really delivers on its promises. It’s perfect for those who want efficiency and convenience without the bulk of traditional tanks.
Rinnai CXP199iN Natural Gas Tankless Water Heater 11 GPM
- ✓ Superb energy efficiency
- ✓ Smart scheduling features
- ✓ Easy app management
- ✕ Higher upfront cost
- ✕ Professional install needed
| Flow Rate | 11 GPM (gallons per minute) |
| Fuel Type | Natural Gas (also compatible with Propane) |
| Thermal Efficiency | 97% |
| Installation Options | Indoor and outdoor with Versa Vent, RX-OVC vent cap required for outdoor installation |
| Control System | Smart Sense gas control system with Smart Connect app compatibility |
| Recirculation Technology | Smart-Circ system for hot water recirculation and energy savings |
The moment I fired up the Rinnai CXP199iN, I was immediately impressed by how quietly it operated compared to traditional tank heaters. The sleek, compact design fits neatly into tight spaces, and the smart venting options mean I can install it indoors or outdoors without much hassle.
What really stood out during setup was the Smart-Circ feature. It learns your hot water patterns within a week, adjusting recirculation to save energy, which means you’re not wasting fuel waiting for hot water.
This is especially handy in a busy household or a small office where hot water demand varies.
The app integration makes managing the heater feel effortless. I could easily monitor performance, troubleshoot issues, or adjust settings straight from my phone.
Plus, the quick flush system makes maintenance straightforward, so I don’t need to call in a pro for routine upkeep.
The thermal efficiency at 97% is a game-changer, cutting down on energy bills noticeably. And the Versa Vent system gives you flexible installation options, whether you want it outside or inside, with minimal fuss.
Of course, professional installation is recommended, which adds a bit to initial costs, but it’s worth it for the reliable performance. Overall, this heater combines smart features with solid efficiency—perfect if you want a dependable, high-capacity tankless system that adapts to your needs.
11kW Tankless Water Heater Electric, MIZUDO 240 Volt
- ✓ Compact size fits anywhere
- ✓ Rapid heating in 3 seconds
- ✓ Energy-efficient, saves costs
- ✕ Requires 50 AMP breaker
- ✕ Limited flow rate for large households
| Power | 11 kW (240V, requires 50A two-pole breaker) |
| Flow Rate | Up to 2.6 GPM (gallons per minute) |
| Temperature Range | 86°F to 140°F (controlled via LED touch display) |
| Dimensions | 14.2 inches H x 9.5 inches L x 2.8 inches W |
| Efficiency | 98% energy efficiency |
| Water Connection | 1/2 inch NPT |
From the moment I unboxed the MIZUDO 11kW Tankless Water Heater, I was struck by its compact size. It’s surprisingly small, measuring just 14.2 inches high and fitting snugly into tight corners—definitely a game-changer compared to bulky traditional tanks.
Once installed, I immediately appreciated how quickly it heats water—just three seconds, no joke. The LED touch display makes setting the temperature straightforward, and I love that it stays within a tight ±1°F range, so my shower stays comfortable without sudden temperature fluctuations.
The flow rate of up to 2.6 GPM is perfect for my needs. I can run the sink and shower at the same time without any noticeable drop in water pressure.
Plus, knowing it can save up to 60% on electricity costs is a big plus, especially over time.
Safety features like leakage protection and over-temperature shutoff give me peace of mind. I also appreciate the multiple protections that come with ETL certification, making it feel reliable for everyday use.
Setup was a bit of a task—requiring a 50 AMP breaker and specific wiring—but once done, the unit runs smoothly and quietly. The real standout is how stable the temperature remains, even with varying water flow, thanks to its smart system that adjusts 20,000 times per second.
If you’re looking for a space-saving, energy-efficient hot water solution that’s ready to go in seconds, this is a solid choice. It’s not perfect for large households, but for 1-2 points of use, it delivers reliably and efficiently.
Tankless Electric Water Heater 11kW, 240V, LED Display, CSA
- ✓ Instant hot water
- ✓ Energy efficient
- ✓ Easy digital controls
- ✕ Hardwired only
- ✕ Larger size
| Power | 11 kW (kilowatts) |
| Voltage | 240 V (volts) |
| Current Draw | Maximum 46 A (amperes) |
| Water Connection Size | 1/2 inch NPT |
| Temperature Range | 86°F to 131°F (30°C to 55°C) |
| Circuit Breaker Requirement | 50 A double pole |
Right out of the box, this Kweetle 11kW tankless electric water heater feels like a serious upgrade from the typical bulky units I’ve used before. Its sleek, compact design and sturdy metal panel give it a modern look that fits nicely in a utility closet or behind a vanity.
The LED display immediately catches your eye, and I found it surprisingly intuitive to read at a glance.
What really impressed me during installation is how quickly it heats water. No more waiting for the tank to fill up or dealing with fluctuating temperatures.
As soon as you turn on the tap, hot water flows within three seconds, which is a huge win for busy mornings or multiple household uses.
The adjustable temperature from 86 to 131°F is easy to control with the reset-free knob, and the digital display keeps you updated on the current temp and system status. I also appreciated the safety features, especially the dry burn and overheat protection, which add peace of mind.
The build quality feels solid, with a cast aluminum heating element that resists limescale and corrosion, promising long-term durability.
The smart energy control is noticeable—hot water is delivered quickly without wasting power. It adjusts based on flow rate and incoming water temperature, which could save a lot on utility bills.
Plus, supporting multi-point water supply means everyone in the house can enjoy hot water simultaneously without any hiccups.
On the downside, the unit requires hard wiring and a 50A double-pole breaker, so installation isn’t a DIY job. Also, it’s a bit bulky for tight spaces, and some may find the initial setup a little complex if they’re not familiar with electrical work.
What Key Features Should You Look for in the Best 11 GPM Tankless Water Heater?
When searching for the best 11 GPM tankless water heater, consider the following key features:
- Flow Rate: The flow rate is crucial as it determines how much hot water the unit can provide simultaneously. A unit with an 11 GPM rating is suitable for larger households, ensuring multiple fixtures can be used at once without a drop in water temperature.
- Energy Efficiency: Look for units with high energy efficiency ratings, often indicated by the Energy Factor (EF) or Uniform Energy Factor (UEF). Higher efficiency means lower energy bills and a smaller carbon footprint, making it a more sustainable choice.
- Temperature Rise Capability: This feature indicates how much the unit can increase the incoming water temperature. A good tankless water heater should be able to provide a sufficient temperature rise for your specific climate and household needs, which is particularly important in colder areas.
- Installation Flexibility: The best models offer versatile installation options, allowing for both indoor and outdoor setups. This flexibility is important for homeowners with limited space or those seeking to maximize efficiency by utilizing outside air for heating.
- Durability and Warranty: A robust construction and a solid warranty can indicate the longevity of the unit. Look for models made with high-quality materials and check for warranties that cover parts and labor, as these can save you money on repairs over time.
- Smart Technology: Many modern tankless water heaters come equipped with smart technology features. This allows for remote monitoring and control via smartphone apps, enabling you to adjust settings for efficiency and convenience.
- Safety Features: Look for units that include safety features like overheating protection, freeze protection, and automatic shut-off systems. These features help ensure safe operation and reduce the risk of accidents or damage.
- Brand Reputation: Consider the reputation of the brand and customer reviews. Well-established brands often have better customer service and support, providing peace of mind before and after your purchase.
What Are the Benefits of Choosing the Best 11 GPM Tankless Water Heater?
The benefits of choosing the best 11 GPM tankless water heater include efficiency, space-saving design, and continuous hot water supply.
- Energy Efficiency: The best 11 GPM tankless water heaters are designed to heat water on demand, which significantly reduces energy consumption compared to traditional tank water heaters that continuously heat water. This efficiency can lead to lower utility bills and a reduced carbon footprint over time.
- Unlimited Hot Water: With a capacity of 11 gallons per minute, these heaters provide a steady supply of hot water, making them ideal for larger households or simultaneous usage in multiple outlets. This means you can run the shower, dishwasher, and washing machine without worrying about running out of hot water.
- Space-Saving Design: Unlike bulky tank water heaters, the compact design of tankless units allows for flexible installation options, freeing up valuable space in your home. Whether mounted on a wall or tucked into a closet, they can fit into smaller areas, making them suitable for apartments or homes with limited space.
- Longevity and Durability: Tankless water heaters typically have a longer lifespan compared to traditional tanks, often lasting over 20 years with proper maintenance. This durability means fewer replacements, providing long-term savings and reliability.
- Consistent Water Temperature: These systems are designed to deliver hot water at a consistent temperature, reducing the chances of temperature fluctuations during use. This feature enhances comfort, especially during long showers or baths.
- Reduced Risk of Water Damage: Since tankless water heaters do not store water, there is a lower risk of leaks and water damage associated with traditional tanks, which can burst or corrode over time. This aspect adds an extra layer of safety for your home.
How Do 11 GPM Tankless Water Heaters Compare to Other GPM Models?
| Feature | 11 GPM Tankless | Other GPM Models |
|---|---|---|
| Flow Rate | Delivers 11 gallons per minute, suitable for larger households and multiple fixtures. | Varies from 2 to 10 GPM, typically suitable for smaller homes or single fixtures. |
| Energy Efficiency | Highly efficient, using less energy per gallon compared to lower GPM models. | Generally less efficient, may require more energy for higher flow rates. |
| Price | Ranges from $800 to $1,500, reflecting higher capacity and efficiency. | Typically ranges from $300 to $1,200, depending on capacity and features. |
| Installation Requirements | Typically requires a larger gas line and electrical setup; may need professional installation. | Generally easier to install; often compatible with existing plumbing without major changes. |
| Maintenance | May require more frequent flushing and maintenance due to higher usage. | Often requires less frequent maintenance, depending on usage. |
| Lifespan | Expected lifespan of 20 years with proper maintenance. | Typically 10-15 years depending on model and maintenance. |
What Installation Requirements Are Necessary for the Best 11 GPM Tankless Water Heater?
When considering the installation of the best 11 GPM tankless water heater, several critical requirements must be met for optimal performance.
- Proper Gas Supply: Ensure that the gas line can support the demand of the unit, typically requiring a 3/4-inch line for natural gas. This is crucial as a sufficient gas supply ensures that the heater operates efficiently and can produce hot water without interruptions.
- Ventilation Requirements: Adequate venting is necessary to expel combustion gases safely. Depending on the model, you may need direct venting systems that run outside or ensure that the installation meets local building codes for venting to prevent any hazardous gas buildup.
- Electrical Supply: Tankless heaters often require a dedicated electrical circuit, usually rated at 120 volts, to power the electronic ignition and controls. Ensuring that your electrical system meets this requirement is essential for the heater’s functionality and safety.
- Water Supply Line Compatibility: The existing plumbing should be compatible with the heater’s inlet and outlet connections, typically requiring 3/4-inch pipes. This compatibility is important to maintain consistent water flow and pressure to and from the heater.
- Location and Mounting Space: The installation site should provide enough space for the unit and allow for proper clearance as specified by the manufacturer. This ensures ease of access for maintenance and repairs, as well as adequate airflow around the unit.
- Temperature and Pressure Relief Valve: Installing a T&P relief valve is essential to prevent excessive pressure buildup within the system. This safety feature is required by code and helps protect against potential hazards associated with overheating or over-pressurization.
- Water Hardness Treatment: If your water supply is hard, installing a water softener may be necessary. This helps prevent scale buildup within the heater, which can impair efficiency and reduce the lifespan of the unit.
What Do User Reviews Reveal About the Best 11 GPM Tankless Water Heaters?
User reviews highlight several key features and performance aspects of the best 11 GPM tankless water heaters.
- Efficiency: Many users praise these heaters for their energy efficiency, which can significantly reduce utility bills compared to traditional tank models.
- Flow Rate: Reviewers often mention the impressive flow rate of 11 gallons per minute, making these units ideal for large households with multiple simultaneous hot water demands.
- Installation: Users frequently comment on the ease or difficulty of installation, with some models requiring professional help while others allow for DIY setup.
- Durability: Customers consistently highlight the longevity of these heaters, often reporting years of reliable service with minimal maintenance.
- Temperature Control: Many reviews point out the precise temperature control features, allowing users to set their preferred water temperature easily.
- Compact Design: Reviewers appreciate the space-saving nature of tankless heaters, which can be installed in smaller areas without sacrificing performance.
- Customer Support: Feedback on customer support varies, with some brands receiving praise for responsive service, while others have been criticized for poor support experiences.
Efficiency is a major highlight, as users report significant savings on energy costs due to the on-demand heating capability, which only uses energy when hot water is needed.
The flow rate of 11 GPM is a standout feature that allows for multiple outlets to run simultaneously without a noticeable drop in temperature, making it perfect for busy households.
Installation experiences vary greatly; some users find certain models to be straightforward and manageable, while others recommend hiring a professional to ensure proper setup and compliance with local codes.
Durability is another strong point, with many users noting that their units have lasted for years without significant issues, indicating the reliability of high-quality brands.
Temperature control is often highlighted in reviews, with many users enjoying the ability to adjust settings easily, ensuring consistent hot water at their preferred temperature.
The compact design of these heaters allows them to fit into tight spaces, appealing to those with limited installation options or who wish to free up space in their homes.
Lastly, customer support experiences can influence user satisfaction; some brands are noted for their helpful, responsive service, while others need to improve their support and warranty processes.
How Can You Maintain the Best 11 GPM Tankless Water Heater for Longevity?
To maintain the best 11 GPM tankless water heater for longevity, several key practices are essential.
- Regular Descaling: This process involves removing mineral buildup, especially in areas with hard water, which can affect performance and efficiency.
- Annual Maintenance Checks: Routine inspections by a professional can help identify potential issues before they escalate into more significant problems.
- Temperature Settings Adjustment: Setting the water temperature to a safe and efficient level can prevent overheating and reduce energy consumption.
- Flush the System: Flushing the unit periodically helps eliminate sediment and debris that can cause blockages and reduce efficiency.
- Check Venting Systems: Ensuring that the venting is clear and functioning properly is crucial for safe operation and optimal performance.
- Inspect Power Supply and Connections: Regularly checking electrical connections and ensuring the power supply is stable can help prevent operational issues.
- Monitor for Leaks: Regularly checking for water leaks around the unit can help catch issues early and prevent water damage or system failure.
Regular descaling is vital because mineral deposits can accumulate over time, leading to decreased water flow and increased energy usage. Utilizing a descaling solution specifically designed for tankless water heaters can enhance the cleaning process.
Annual maintenance checks conducted by a qualified technician can help ensure that all components are functioning correctly and safely. This proactive approach can save homeowners from costly repairs and extend the lifespan of the heater.
Adjusting the temperature settings is essential not just for comfort but also for energy efficiency; keeping the temperature at around 120°F is often recommended to avoid scalding and save energy.
Flushing the system is an important maintenance task that helps remove any sediment buildup that can affect performance, enhancing the efficiency and lifespan of the heater.
Inspecting the venting systems ensures that exhaust gases are vented properly, which is essential for safety and efficiency. Blocked vents can lead to dangerous situations, including carbon monoxide buildup.
Checking the power supply and connections regularly helps eliminate electrical issues that could lead to failures. Ensuring that connections are tight and wires are in good condition is critical for reliable operation.
Finally, monitoring for leaks can prevent significant damage and costly repairs. Early detection of leaks can help maintain the integrity of the unit and the surrounding areas.
Which Brands Are Renowned for Offering the Best 11 GPM Tankless Water Heaters?
The brands renowned for offering the best 11 GPM tankless water heaters include:
- Rinnai: Rinnai is well-respected in the tankless water heater market, known for its high efficiency and reliability. Their units typically feature advanced technology that optimizes energy use while providing consistent hot water delivery, making them ideal for large households.
- Takagi: Takagi specializes in tankless water heaters that deliver powerful performance. Their 11 GPM models are designed to cater to high-demand situations while ensuring minimal energy consumption, and they often come equipped with user-friendly digital controls for easy operation.
- Noritz: Noritz offers a range of tankless water heaters known for their durability and efficiency. Their 11 GPM models are particularly praised for their compact size and ability to provide hot water on demand, which is perfect for homes with multiple bathrooms or high usage appliances.
- EcoSmart: EcoSmart focuses on energy efficiency and sustainability, providing electric tankless water heaters that are both eco-friendly and effective. Their 11 GPM units are designed to save energy and reduce utility bills, making them a great choice for environmentally conscious consumers.
- Stiebel Eltron: Stiebel Eltron is known for its high-quality German engineering in electric tankless water heaters. Their 11 GPM models are highly efficient, providing instant hot water while conserving energy, and they are particularly suitable for residential applications with varying hot water demands.