Choosing the best tankless water heater depends on your household’s hot water demands, energy source preferences, and budget. The EcoSmart ECO 27 stands out as the best overall for its high efficiency and versatility, ideal for larger homes. The Rinnai RX199iN offers exceptional performance with smart features for those seeking premium quality. However, the main challenge is balancing upfront costs with long-term energy savings, as some models require higher initial investment while others excel in affordability. Keep reading to see how these options compare and which might be right for your home.
Key Takeaways
- Electric models like the EcoSmart ECO 27 and Rheem RTEX series deliver high efficiency suitable for smaller to medium households.
- Gas-powered options such as the Rheem and FOGATTI provide higher flow rates, better for larger homes or heavy-duty use.
- Flow rate capacity is a key factor—consider your household’s hot water needs when choosing a model.
- Smart features and digital displays are becoming more common, adding convenience but often at a higher price.
- Installation complexity varies significantly; gas models typically require professional setup, while electric units may be easier for DIY installation.
More Details on Our Top Picks
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW
The EcoSmart ECO 27 stands out for its impressive energy efficiency of 99.8%, making it ideal for users seeking to lower utility bills while ensuring reliable hot water in cold climates. Its digital temperature control in 1-degree increments offers precise adjustments, and the self-modulating technology optimizes energy use based on demand, outperforming models like the Rheem RTEX-24 in efficiency. However, its demand for multiple circuit breakers and specific electrical setup can complicate installation, especially in older homes. This unit is best suited for households with dedicated electrical capacity and those prioritizing energy savings. Compared to electric models with lower wattage, the ECO 27 provides higher flow rate control but demands a more robust electrical system, which might be a barrier for some.
Pros:- Exceptional energy efficiency at 99.8%
- Precise temperature control in 1-degree steps
- Suitable for cold climates and high demand use
- Self-modulating technology for energy savings
Cons:- Requires multiple heavy-duty circuit breakers and proper electrical setup
- Limited inlet water temperature tolerance may affect performance in some areas
Best for: Homeowners in cold climates needing high energy efficiency and reliable hot water for multiple fixtures.
Not ideal for: Owners of small apartments or homes with limited electrical capacity, due to its high wiring requirements.
- Power:27 kW
- Voltage:240V
- Flow Rate:2.7 to 6.5 GPM
- Dimensions:17 x 17 x 3.5 inches
- Weight:11 lbs
- Temperature Range:Adjustable in 1-degree increments
Bottom line: This pick is best for energy-conscious users with sufficient electrical infrastructure seeking high performance in cold environments.
Titan Electric Tankless Water Heater
The Titan Electric Tankless Water Heater offers reliable on-demand hot water with a 220V input and a high maximum current of 54 amps, making it a strong choice for homes needing quick hot water. Its compact size and high power capacity allow it to deliver instant hot water efficiently, outperforming lower-powered models like the EcoSmart ECO 11 in flow rate. The primary tradeoff is that it demands a dedicated 220V circuit and professional installation, which might be a hurdle for DIY enthusiasts or in homes with limited electrical capacity. This heater suits smaller households or those with straightforward hot water needs, but it may not be ideal for larger families expecting multiple simultaneous fixtures.
Pros:- Provides instant hot water on demand
- High power capacity ensures efficient heating
- Compact and space-saving design
- Suitable for small to medium households
Cons:- Requires a 220V power supply, limiting flexibility
- Installation may need professional electrical work
Best for: Households with simple hot water demands and existing 220V wiring who value instant, on-demand heating.
Not ideal for: Larger families or multi-bathroom homes that require higher flow rates and multiple simultaneous hot water points.
- Voltage:220 V
- Max Amps:54 A
Bottom line: This heater is perfect for smaller households seeking quick hot water with minimal space requirements but needs adequate electrical wiring.
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
The Rheem RTEX-24 combines space-saving design with exceptional efficiency, boasting a 99.8% energy rating and a flow rate of 5.9 GPM. It offers adjustable temperature control from 80-140°F, making it versatile for various household needs. Compared to the EcoSmart ECO 27, the RTEX-24 might demand a slightly more complex electrical setup, requiring three 40A double pole breakers. Its performance heavily depends on groundwater temperature, which can vary by location, but it excels in homes with adequate electrical infrastructure that want reliable, continuous hot water. Its compact form makes it suitable for small spaces, yet its high power needs could be a barrier for some installations.
Pros:- Provides continuous hot water on demand
- Highly energy efficient at 99.8%
- Space-saving, wall-mountable design
- Adjustable temperature from 80-140°F
Cons:- Requires three 40A double pole breakers, complicating installation
- Performance depends on groundwater temperature
Best for: Homeowners with existing electrical capacity seeking efficient, continuous hot water with precise temperature control.
Not ideal for: Properties with limited electrical capacity or those who prefer simpler installation without high circuit demands.
- Power Source:Corded Electric
- Wattage:24 KW
- Voltage:240V
- Flow Rate:5.9 GPM
- Maximum Temperature:140°F
- Efficiency:99.8%
Bottom line: Ideal for users with robust electrical systems who want reliable, adjustable hot water in a compact form.
14kW Tankless Electric Water Heater with LED Display, 240V, ETL Certified, Up to 3.38 GPM
The 14kW Electric Tankless Water Heater offers a practical solution for point-of-use hot water needs with a flow rate up to 3.38 GPM. Its LED display simplifies temperature monitoring, and its safety features add peace of mind. While it is energy-efficient and easy to install in small spaces, its flow rate may be insufficient for larger households or simultaneous fixtures, unlike the Rheem RTEX-24. Additionally, it requires a dedicated 240V/60AMP circuit, which could mean electrical upgrades for some homes. This heater is best for singles or small families with modest hot water demands who prioritize compact size and straightforward operation, but it isn’t suitable for high-demand applications.
Pros:- Compact size fits easily into small spaces
- Provides instant hot water at point-of-use
- Energy-efficient operation
- Easy-to-read LED display
Cons:- Flow rate may be insufficient for multiple fixtures
- Requires electrical upgrades in some installations
Best for: Small households or individual users needing reliable hot water at a single point or for minimal fixtures.
Not ideal for: Larger households or homes with multiple bathrooms, due to limited flow rate.
- Power:14 kW
- Voltage:240V
- Flow Rate:up to 3.38 GPM
- Temperature Range:86°F – 140°F
- Dimensions:14.2″H x 9.5″L x 3.1″W
- Certifications:ETL
Bottom line: This heater suits small households seeking easy, space-efficient hot water without high flow demands, but not for larger families.
110V Tankless Electric Water Heater, 3000W, Instant Hot Water with Digital Display for Kitchen & Bathroom
This 110V electric model stands out for its compact size and ease of installation, making it ideal for small spaces like kitchens, RVs, or bathroom sinks where a full-sized system isn’t practical. Unlike larger electric units such as the EcoSmart ECO 11, it offers instant hot water with a high thermal efficiency of 98%, but it’s limited to low flow rates—not suitable for showers. Its digital display and safety protections add convenience and peace of mind, yet vertical installation only could be restrictive in tight spaces. Compared to gas options like the FOGATTI or Rheem RTG-70DVLN, this model is more energy-efficient but cannot handle higher flow demands, making it perfect for point-of-use applications rather than whole-house setups.
Pros:- Space-saving, wall-mounted design fits small spaces easily
- High thermal efficiency of 98% reduces energy waste
- Includes multiple safety protections and a clear digital display
Cons:- Limited to low flow rates, unsuitable for showers
- Vertical installation only, no horizontal mounting option
Best for: Buyers needing a compact, energy-efficient solution for kitchen or bathroom sinks, especially in small or mobile spaces.
Not ideal for: Households expecting to run multiple fixtures simultaneously or seeking a shower-capable electric heater—this model is too limited in flow rate.
- Power:3000W
- Voltage:110V
- Water Temperature Rise:82°F (0.3 GPM) – 131°F (0.5 GPM)
- Material:Stainless steel and ABS
- Waterproof Rating:IPX4
- Installation Type:Wall-mounted
Bottom line: This pick makes the most sense for those who need instant hot water at a single point in compact spaces and prioritize energy efficiency over flow capacity.
Rheem RTG-70DVLN-3 High Efficiency Indoor Tankless Natural Gas Water Heater 7.0 GPM
Compared with electric options like the Rheem 18kW model, the RTG-70DVLN-3 offers a higher flow rate of 7.0 GPM, making it suitable for households with 2-3 bathrooms where multiple fixtures may be used simultaneously. It’s powered by natural gas, providing reliable hot water without the electric load, but requires professional installation and a natural gas line. Its compact, wall-mountable design makes it a good fit for indoor spaces, yet it isn’t designed for very large households or those without gas access. While it excels in efficiency and continuous hot water, the need for proper venting and professional setup is a notable tradeoff, especially compared to electric models that are simpler to install.
Pros:- High flow rate of 7.0 GPM supports multiple fixtures
- Reliable hot water with hot-start programming prevents cold bursts
- Compact, space-saving design for indoor installation
- Highly efficient with natural gas
Cons:- Requires professional installation and gas connection
- Limited to natural gas, no electric backup
- Not suitable for very large households with higher hot water demand
Best for: Homeowners with natural gas service needing a reliable, high-flow system for multiple bathrooms.
Not ideal for: Renters or those without gas access, as installation complexity and costs are significant barriers.
- Flow Rate:7.0 GPM
- BTUs:160,000
- Fuel Type:Natural Gas
- Application:Indoor
- Design:Space-saving, wall-mountable
Bottom line: This system works best for gas-equipped homes needing dependable hot water for several fixtures simultaneously, with installation professionalism as a key consideration.
FOGATTI Natural Gas Tankless Water Heater Indoor – Max 7.5 GPM 170,000 BTU, CSA Certified, Compact Design, Instant Hot Water
The FOGATTI model is designed for households with higher hot water needs, delivering up to 7.5 GPM and 170,000 BTU, surpassing many gas models in flow capacity. Its compact form allows indoor installation, and it offers precise temperature control, making it suitable for busy homes with multiple outlets. Compared to the Rheem gas heater, it provides a slightly higher flow rate, but performance can be affected at high altitudes and it requires proper ventilation and professional installation. While its high capacity makes it ideal for larger households, this comes with increased complexity and cost—less ideal for smaller homes or those without gas connections.
Pros:- Provides instant, high-flow hot water for multiple outlets
- High BTU output ensures rapid heating and supply
- Compact and easy to install indoors
- CSA certified and durable construction
Cons:- Requires professional venting and gas hookup
- Performance may be impacted at high altitudes
- Installation costs can be significant
Best for: Large families or homes with high simultaneous hot water use who need reliable, high-capacity gas heating.
Not ideal for: Small households, renters, or homes without proper ventilation, due to installation needs and performance constraints at high altitudes.
- Flow Rate:7.5 GPM
- Heat Output:170,000 BTU
- Power Source:Natural Gas
- Application:Indoor
- Certifications:CSA
Bottom line: This heater is well-suited for large households needing high flow rates, provided the installation setup and altitude considerations are managed properly.
Rheem 18kW 240V Tankless Electric Water Heater, Gray
This Rheem electric model provides up to 4.4 GPM, making it a solid choice for smaller households or point-of-use applications compared to larger electric units like the EcoSmart ECO 27. Its self-modulating system adjusts power to match demand, conserving energy, while the digital LED display offers precise temperature control. The copper heating elements ensure durability, but the limited flow rate makes it less suitable for simultaneous multiple fixtures—especially in larger households. Installation requires a dedicated 240V circuit and professional electrical work, which may add to upfront costs. Overall, this model balances efficiency and performance for modest hot water needs, but isn’t designed for high-demand scenarios.
Pros:- Digital display with precise temperature control
- Self-modulation enhances energy efficiency
- Durable copper heating elements
Cons:- Limited flow rate for bigger households
- Requires dedicated 240V electrical circuit
Best for: Small households or point-of-use applications where a compact, efficient electric heater is needed.
Not ideal for: Large families or homes with multiple simultaneous outlets, as the flow rate may be insufficient.
- Power:18kW
- Voltage:240V
- Flow Rate:up to 4.4 GPM
- Material:Copper
- Installation:Bottom 3/4 inch NPT
Bottom line: This electric heater suits small homes or specific fixture points, offering efficiency without the bulk of larger systems.
Rinnai RX199iN Condensing Smart Sense Tankless Water Heater, Indoor/Outdoor, Up to 11.1 GPM, 199,000 BTU
The Rinnai RX199iN offers a remarkable combination of high flow rate and versatility, supporting up to 11.1 GPM for large households or busy commercial settings. Its ability to be installed indoors or outdoors adds flexibility, with smart controls and high efficiency (UEF 0.98) making it a standout for energy-conscious users. Compared to smaller gas units like FOGATTI or Rheem, it accommodates more fixtures simultaneously, but professional installation and venting are essential. The WiFi control is a bonus, yet the separate purchase and outdoor venting requirements add complexity. This model is best for those seeking robust performance and smart features, willing to handle the installation demands.
Pros:- Supports up to 11.1 GPM for multiple outlets
- Indoor/outdoor versatility for installation options
- High efficiency with UEF 0.98 reduces energy costs
- Smart controls for monitoring and maintenance
Cons:- Professional installation required, including venting
- WiFi control sold separately
- Outdoor use needs vent cap for weather protection
Best for: Large households or small commercial spaces needing high flow capacity with flexible installation options.
Not ideal for: Homeowners without access to proper venting or those seeking an electric-only solution.
- Flow Rate:Up to 11.1 GPM
- BTU:199,000
- Gas Type:Natural Gas or Propane
- Installation:Indoor or outdoor
- Energy Factor:UEF 0.98
Bottom line: Ideal for large households or commercial applications demanding high flow and flexible placement, with the understanding that professional setup is necessary.
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240V
The EcoSmart ECO 11 stands out for its ultra-compact design, making it an excellent choice for small spaces like sinks, bathrooms, or RVs. Its self-modulating technology ensures energy efficiency by adjusting power based on demand, which can significantly reduce electricity costs compared to less efficient models. The digital temperature control allows precise adjustments within an 80-140°F range, providing consistent hot water. However, its flow rate of 1.3 to 3.1 GPM makes it less suitable for colder climates or larger fixtures, where water demand exceeds its capacity. Unlike the Rheem RTEX-11, which offers a slightly higher flow rate, this unit is best for low-flow needs and small households. The main tradeoff is its limited capacity, but for its niche, it performs reliably and efficiently.
Pros:- Compact and space-saving design perfect for tight areas
- High thermal efficiency at 99%
- Digital temperature control for precise adjustments
- Self-modulating technology reduces energy waste
Cons:- Limited flow rate reduces effectiveness in cold climates
- Requires a dedicated 54A electrical circuit, which may need upgrade
Best for: Single-sink applications, small bathrooms, or RV owners needing on-demand hot water in limited spaces.
Not ideal for: Large households or cold climates requiring higher flow rates and greater hot water capacity.
- Power:13 kW
- Voltage:240 V
- Amperage:54 A
- Flow Rate:1.3 to 3.1 GPM
- Temperature Range:80-140°F
- Dimensions:11.5 x 8 x 3.75 inches
- Efficiency:99%
- Special Features:Self-modulating technology, digital temperature control
Bottom line: This model is ideal for small-scale, point-of-use needs where space and energy efficiency matter most.
Rheem Performance RTEX-11 11kW 240V Tankless Electric Water Heater
The Rheem RTEX-11 offers a reliable, continuous hot water supply with a sleek wall-mount design, making it a strong contender for small households or point-of-use applications. Its self-modulating technology ensures energy-efficient operation, similar to the EcoSmart ECO 11, but it provides a higher flow rate of 2.68 GPM, making it more adaptable for slightly larger demands. The digital control is intuitive, allowing easy temperature adjustments. Compared to the EcoSmart ECO 11, this unit delivers more hot water per minute, but it still struggles in very cold climates or larger fixtures. Its maximum pressure of 150 PSI ensures durability under high-pressure conditions, which is a plus for residential use. The main tradeoff is that, like the EcoSmart, it’s limited to point-of-use and small-scale applications, meaning it’s not suitable for whole-house requirements.
Pros:- Space-efficient, wall-mount design saves room
- Provides continuous hot water on demand
- Energy-efficient with self-modulating technology
- Easy-to-use digital temperature control
Cons:- Flow rate may be insufficient for larger households or multiple fixtures
- Requires proper electrical wiring and installation
Best for: Small households or apartments needing continuous hot water at a single fixture or small area.
Not ideal for: Large families or homes with multiple simultaneous hot water demands, as flow rate may fall short.
- Power Source:AC
- Wattage:11 kW
- Voltage:240 V
- Flow Rate:2.68 GPM
- Heat Output:11 Kilowatts
- Efficiency:99.8%
- Maximum Pressure:150 PSI
- Mount Type:Wall
Bottom line: This pick suits small households seeking reliable, on-demand hot water without taking up much space.
How We Picked
The products in this roundup were selected based on performance, energy efficiency, ease of installation, durability, and value for money. We prioritized models that serve a broad range of household sizes and hot water demands, ensuring options for both small apartments and large families. Cost of operation and maintenance were also key factors, alongside user-friendly features like digital displays and smart controls. Our ranking aims to highlight not just the best-performing units but also those offering good long-term value and suitability for different user needs.Factors to Consider When Choosing Best Tankless Water Heaters
When choosing a tankless water heater, several factors come into play beyond just initial cost. Understanding these can help you avoid common pitfalls and select a model that truly fits your home’s hot water demands and energy preferences. From flow rate to energy source, each aspect impacts long-term satisfaction and operational costs.Flow Rate and Household Size
Knowing your household’s hot water needs is essential. Larger families or homes with multiple bathrooms require higher flow rate units, typically measured in GPM (gallons per minute). Underestimating this can result in insufficient hot water during peak times, while overspending on a high-capacity unit may be unnecessary for small households. Carefully assess your use patterns before choosing a model.
Energy Source and Efficiency
Electric models tend to be easier to install and maintain, often offering high efficiency, especially in smaller homes. Gas units, including natural gas and propane, generally deliver higher flow rates suitable for larger households but require venting and professional installation. Consider your available energy infrastructure and long-term operational costs when selecting.
Installation and Space Requirements
Some units are compact and designed for easy mounting, making them ideal for tight spaces or DIY installation. Others may need professional setup due to venting or electrical requirements. Proper placement can improve efficiency and ease of access for maintenance, so evaluate your home’s layout carefully.
Cost, Maintenance, and Longevity
Initial costs vary widely, but factoring in ongoing maintenance and energy bills is crucial. Gas models often have higher upfront costs but can be more economical over time for high hot water demand. Electric units typically cost less initially but may have higher operational costs depending on local energy prices. Longevity depends on build quality and maintenance practices, so choose a reputable brand.
Smart Features and User Control
Many modern units include digital displays, Wi-Fi connectivity, and smart controls, enhancing usability and allowing remote monitoring. These features can improve convenience but often come with a higher price tag. Decide whether smart capabilities are worth the extra investment based on your tech preferences and budget.
Frequently Asked Questions
Can I install a tankless water heater myself?
While some electric models are designed for DIY installation, most gas units and high-capacity electric units require professional setup due to complex venting, electrical wiring, and safety considerations. Improper installation can lead to safety hazards, inefficiency, or voided warranties. If you’re comfortable with technical tasks and local codes permit, a basic electric unit might be manageable; otherwise, hiring a licensed technician is recommended.
How long do tankless water heaters typically last?
Most tankless water heaters have a lifespan of about 20 years with proper maintenance. Regular flushing to prevent mineral buildup, especially in hard water areas, can extend their longevity. Investing in a quality unit and following manufacturer guidelines for maintenance ensures your system performs reliably over the years.
Are electric tankless water heaters suitable for large households?
Electric units generally have lower flow rate capacities, making them less ideal for large households with high simultaneous hot water demands. They work best for small to medium homes or point-of-use applications. For bigger households, gas models or larger electric units with higher GPM ratings are usually better suited, though they come with higher installation costs.
What is the typical installation cost for a tankless water heater?
Installation costs vary based on the unit type, complexity, and local labor rates. Electric models tend to be less expensive to install, often ranging from $500 to $1,500. Gas units or those requiring venting and gas line upgrades can cost $2,000 or more. Planning for professional installation ensures safety and compliance but is an important part of your total investment.
Is it worth paying extra for smart features?
Smart features add convenience by enabling remote control, diagnostics, and usage monitoring. For tech-savvy users or those seeking more control over energy consumption, these features can justify the additional cost. However, if you prefer simplicity or want a more budget-friendly option, models without smart features still perform effectively, making this a matter of personal preference.
Conclusion
For most homes, the EcoSmart ECO 27 offers the best balance of performance, efficiency, and affordability, making it the ideal choice for the average household. Those seeking premium features and maximum performance should consider the Rinnai RX199iN, especially for larger or demanding households. Budget-conscious buyers will find good value in smaller electric models like the EcoSmart ECO 11. If you have a large household or high hot water demand, a gas model such as the FOGATTI Natural Gas Tankless Water Heater provides higher flow rates, though at a higher installation cost. Ultimately, your choice should reflect your household size, energy source preference, and budget constraints.
