Finding the best tankless water heater electric premium can be challenging due to the variety of features, sizes, and price points. The Rheem RTEX-36 stands out for its powerful performance and adjustable temperature control, making it ideal for larger households. The Electrolux 18kW model offers smart Wi-Fi features, perfect for tech-savvy users. These options highlight the key tradeoffs: higher capacity versus smart features and budget considerations. Continue reading for a detailed breakdown of the top models available in 2026.
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Key Takeaways
- Top-performing models balance high flow rates with reliable temperature control, essential for larger households.
- Smart features like Wi-Fi are increasingly common but often come at a higher price and can add complexity.
- Wattage and flow rate vary significantly, impacting suitability for different household sizes and hot water demands.
- Build quality and certification ensure longevity, especially for models designed for whole-house use.
- Price differences reflect capacity, features, and brand reputation, making it important to match a model to specific needs.
| tankless water heater electric premium | Voltage | Power | Flow Rate |
|---|---|---|---|
| Rheem RTEX-36 36kW Electric Ta | 240V | 36kW | — |
| Westinghouse 24kW Electric Tan | 240V | 24kW | 5.6 GPM |
| 36kW Electric Tankless Water H | 240V | 36kW | 8.7 GPM |
| ThermoMate 18kW Tankless Elect | 240V | 18kW | 4.4 GPM |
| 14kW Tankless Electric Water H | 240V | 14kW | 3.38 GPM |
| Electrolux 18kW Tankless Elect | 240 V | 18 KW | 4.2 GPM |
| Stiebel Eltron Tempra 29 Plus | 240V | 28.8kW | — |
| Rheem 240V Tankless Water Heat | 240V | 13kW | up to 3.17 GPM |
| Westinghouse 11kW Tankless Ele | 240V | 11kW | 2.6 GPM |
| Rheem RTEX-27 240V 3 Heating C | 240V | — | — |
| 27kW Tankless Water Heater Ele | 240V | 27kW | 7.4 GPM |
| Rheem RTEX-24 24kW 240V Electr | 240V | 24kW | 5.9 GPM |
| 18kW Tankless Electric Water H | 240V | 18kW | — |
More Details on Our Top Picks
Rheem RTEX-36 36kW Electric Tankless Water Heater, 240V, Adjustable Temperature Control, 3/4 in. NPT Connection
The Rheem RTEX-36 stands out for its impressive 36kW power output, making it suitable for larger households demanding multiple outlets simultaneously. Compared with the Westinghouse 24kW model, it offers significantly higher flow capacity, ensuring hot water for more fixtures without sacrificing reliability. However, this power comes with a need for a substantial electrical setup, which can complicate installation. Its adjustable temperature control adds flexibility for personalized comfort, and its compact design makes it versatile for various installation environments. The main tradeoff is the higher electrical requirement, potentially increasing installation costs. This pick is ideal for homes with high hot water demand that can accommodate the electrical load.
Pros:- High power output provides reliable hot water for multiple fixtures
- Adjustable temperature for personalized comfort
- Compact design allows flexible installation
Cons:- Requires a 240V, 36kW electrical supply, which can be complex and costly to install
- Installation may require professional electrical work due to high power requirements
Best for: Large households or homes with multiple bathrooms needing high hot water capacity
Not ideal for: Small apartments or homes with limited electrical capacity due to its high power draw
- Power:36kW
- Voltage:240V
- Connection:3/4 in. NPT
- Temperature Control:Adjustable
Our verdict“This is the best choice for large households that require high flow rates and have the electrical capacity to support it.”
Westinghouse 24kW Electric Tankless Water Heater, Wi-Fi, Whole House Use
The Westinghouse 24kW unit offers a smart, connected experience with Wi-Fi control, making it a standout for tech-savvy users who want remote management. It can deliver up to 5.6 GPM, which is sufficient for small to medium households, and its compact size fits tight spaces comfortably. When compared with the Rheem RTEX-36, it trades off some capacity for smart features and easier installation. Its safety features like overheat, dry-fire, and leak protection add peace of mind, but the electrical demands—requiring a 240V/100A supply—may limit its compatibility with some homes. The flow rate can also fluctuate in cold climates, which might impact performance during winter months. This option makes sense for homeowners seeking integrated smart control in a space-efficient unit.
Pros:- Wi-Fi connectivity with app control, compatible with Alexa and Google Home
- Compact size fits into small or tight spaces
- Safety features ensure reliable operation
Cons:- Requires a 240V/100A electrical supply, which may need upgrades
- Flow rate may be affected by inlet temperature, especially in cold weather
Best for: Homeowners with small to medium homes who want smart features and space-saving design
Not ideal for: Large households or homes with insufficient electrical capacity or very high hot water demands
- Power:24kW
- Voltage:240V
- Flow Rate:5.6 GPM
- Features:Wi-Fi, Alexa & Google Home compatible
Our verdict“Ideal for small to medium homes that value smart control and space efficiency over maximum flow capacity.”
36kW Electric Tankless Water Heater 240V ETL Certified WiFi
The 36kW model offers a high flow rate of 8.7 GPM, making it suitable for larger homes with multiple bathrooms or high hot water needs. Compared with the Rheem RTEX-36, it emphasizes safety and energy efficiency with self-modulating technology and multiple safety protections. Its WiFi control adds convenience for managing temperature remotely. The main drawback is the requirement for a 300A household electrical service, which can be a significant upgrade and may limit its applicability. It’s best suited for homes with the electrical capacity to support this level of power, especially in moderate climates where flow rate impacts are less severe. This unit balances high capacity with smart features for demanding households.
Pros:- High flow rate supports multiple fixtures simultaneously
- Energy-efficient self-modulating technology reduces power use
- WiFi control for remote management
Cons:- Requires a substantial 300A electrical supply, increasing installation complexity
- Installation generally needs professional electrical work
Best for: Homes with high hot water needs and existing electrical infrastructure capable of supporting 300A service
Not ideal for: Small or electrically limited homes, or those in very cold climates that reduce flow rate performance
- Power:36kW
- Voltage:240V
- Flow Rate:8.7 GPM
- Certifications:ETL
Our verdict“Best suited for large homes with high hot water demand and robust electrical capacity.”
ThermoMate 18kW Tankless Electric Water Heater, 4.4 GPM, ETL Certified
The ThermoMate 18kW unit provides adequate hot water for 2-3 fixtures, making it a good fit for small households or apartments. Compared with the Rheem RTEX-36 and higher-capacity models, it offers a lower power draw and smaller size, but at the expense of flow rate and capacity. Its smart temperature modulation and safety features make it reliable for everyday use, though the electrical requirement of 150 Amps could be a hurdle for some setups. It excels where space is limited and demand is moderate, but it’s not suitable for larger households or high-demand scenarios. This unit is a strong choice for those upgrading from traditional tank heaters in small spaces.
Pros:- Compact, space-saving wall-mounted design
- Smart temperature modulation for consistent delivery
- Built-in safety protections
Cons:- Electrical requirement of 150 Amps may require electrical upgrades
- Limited flow rate restricts use in larger households
Best for: Small households or apartments needing reliable hot water without high electrical loads
Not ideal for: Large families or homes with high simultaneous hot water needs, due to limited flow rate
- Power:18kW
- Flow Rate:4.4 GPM
- Voltage:240V
- Certifications:ETL, UL-499, CAN/CSA-C22.2
Our verdict“Ideal for small homes and apartments seeking dependable hot water with minimal space requirements.”
14kW Tankless Electric Water Heater, On Demand, 240V, 3.38 GPM
The 14kW model offers a compact and efficient solution for point-of-use needs, supporting 2-3 fixtures with a flow rate of 3.38 GPM. Compared with larger units like the ThermoMate 18kW, it’s more affordable and easier to install, but with limited capacity that suits smaller households or specific points like a bathroom sink or kitchen. Its stable temperature control and safety features make it reliable for everyday use, although its flow rate might be insufficient for high-demand applications or larger households. This model is best for users prioritizing affordability and space-saving design without needing simultaneous high flow rates. It’s not suited for homes with multiple bathrooms or high hot water demand.
Pros:- Compact size and easy to install
- Stable temperature and safety protections
- Cost-effective solution for limited hot water needs
Cons:- Flow rate may be insufficient for high-demand scenarios
- Requires a dedicated 60A circuit breaker and proper wiring
Best for: Small households or individual points of use where cost and space are primary concerns
Not ideal for: Larger households or applications requiring high flow rates at multiple fixtures simultaneously
- Power:14kW
- Flow Rate:3.38 GPM
- Voltage:240V
Our verdict“Perfect for small-scale applications needing reliable hot water without high capacity demands.”
Electrolux 18kW Tankless Electric Water Heater, 240V, WiFi, Max 4.2 GPM
This Electrolux model stands out for combining a high flow rate of 4.2 GPM with smart features like WiFi and voice control, making it ideal for households that want quick, on-demand hot water at multiple points. Compared to the Westinghouse WiFi unit, this heater offers a higher flow capacity, but it demands a more complex electrical setup, which could complicate installation. Its compact, wall-mounted design saves space, and the high energy efficiency can reduce electricity bills. However, the unit’s one-year warranty and electrical requirements mean it’s better suited for those comfortable with electrical work or willing to hire professionals.
Pros:- High flow rate suitable for whole-house use
- Smart WiFi and voice control for remote management
- Compact wall-mounted design saves space
- Energy-efficient operation reduces costs
Cons:- Requires specific electrical setup (2 x 240V/40A breakers)
- Installation can be complex and potentially costly
- Limited warranty of only 1 year
Best for: Households needing reliable hot water for 2-3 points of use with smart home integration.
Not ideal for: Small apartments with limited electrical capacity or buyers seeking a longer warranty period.
- Power:18 KW
- Voltage:240 V
- Flow Rate:4.2 GPM
- Maximum Temperature:140°F
- Dimensions:14.1″ W x 18.7″ H
- Weight:15.4 pounds
- Material:Iron housing
- Special Features:WiFi & Voice Control, Scale Inhibitor, ETL Certified, Stable Temperature
Our verdict“This pick is best for tech-savvy homeowners wanting a capable, space-saving unit with smart features.”
Stiebel Eltron Tempra 29 Plus Electric Tankless Water Heater, 28.8kW, 240V
The Tempra 29 Plus excels at providing continuous hot water for larger households, thanks to its substantial 28.8kW power and multiple temperature presets. Its sleek, space-efficient design makes it a good alternative to bulkier models like the Rheem RTEX-27, which offers similar power but with fewer preset options. The need for dedicated 240V wiring and a 200A service can be a hurdle, requiring professional installation and significant electrical capacity. This model makes the most sense for homes with robust electrical systems and a demand for reliable, simultaneous hot water supply.
Pros:- Provides continuous hot water for multiple points
- Multiple temperature presets for customization
- Space-saving, sleek design
- Durable build with reliable performance
Cons:- Requires professional installation and high electrical capacity
- High power consumption increases operational costs
- Less suitable for homes with weak electrical systems
Best for: Families with high water demand and existing electrical infrastructure capable of supporting heavy-duty units.
Not ideal for: Small apartments or homes with limited electrical capacity, due to its high power requirements.
- Power:28.8kW
- Voltage:240V
- Temperature presets:2
- Wiring:8 gauge copper
- Breaker requirement:3 x 40 amp breakers
- Minimum service:200 amp
Our verdict“Ideal for large households with strong electrical wiring seeking reliable, continuous hot water.”
Rheem 240V Tankless Water Heater RTEX-13
The Rheem RTEX-13 offers a practical balance of efficiency and control, with an external digital thermostat that provides ±1°F accuracy, making it easier to fine-tune water temperature than some other models like the Westinghouse WiFi heater. Its 3.17 GPM flow rate suits smaller households or single-point applications, and durable copper heating elements promise long-term performance. Compared with larger, high-capacity models, this unit’s straightforward installation and simple digital interface appeal to DIY enthusiasts or those with basic electrical upgrades. However, its limited flow rate means it’s less suited for homes with multiple simultaneous hot water demands.
Pros:- Highly energy-efficient with 99.8% efficiency
- External digital thermostat for precise temperature control
- Easy to install with included adapters
- Durable copper heating elements
Cons:- Flow rate may be insufficient for larger households
- Requires 240V power, possibly needing electrical upgrades
- Installation complexity for some users
Best for: Individuals or small families needing precise temperature control at a single point of use.
Not ideal for: Large households or multi-point hot water needs, due to limited flow capacity.
- Voltage:240V
- Model:RTEX-13
- Flow Rate:up to 3.17 GPM
- Power:13kW
- Energy Efficiency:99.8%
- Water Connection:1/2 inch NPT
- Temperature Control:External digital +/- 1°F
Our verdict“Best for those who value precise control and straightforward installation for single-point hot water needs.”
Westinghouse 11kW Tankless Electric Water Heater 240V with WiFi and Smart Control
This Westinghouse model is tailored for smaller or single-point applications, offering an exceptionally fast hot water delivery in just 3 seconds, thanks to its 11kW power. Its smart WiFi and voice control capabilities enhance convenience, especially for tech-minded users who want remote adjustments. Its compact size makes it ideal for tight spaces, and anti-scale technology adds to its ease of maintenance. However, the limited flow rate of 2.6 GPM restricts its use to single fixtures or small households, unlike the higher-capacity Rheem or Electrolux models. It’s a strong choice for single-point use but less suitable for whole-house applications.
Pros:- Instant hot water in 3 seconds
- Smart WiFi and voice control compatibility
- Compact wall-mount design
- Anti-scale technology for durability
Cons:- Flow rate limited to 2.6 GPM
- Requires dedicated 60A double-pole breaker
- Mostly suited for single-point applications
Best for: Single-point applications or small households seeking fast hot water with smart controls.
Not ideal for: Large families or multiple simultaneous hot water points, due to flow limitations.
- Power:11kW
- Voltage:240V
- Flow Rate:2.6 GPM
- Connections:1/2″ NPT
- Certifications:ETL
- Protection Features:Leakage, overheat, dry-fire, over-voltage
Our verdict“This unit is perfect for singles or small homes prioritizing speed and smart features over capacity.”
Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
The Rheem RTEX-27 offers a significant upgrade over smaller models, featuring three heating chambers for more robust hot water output and self-modulation technology that adjusts power consumption based on demand. Its digital thermostatic control ensures precise temperature setting, and the bottom water connections facilitate easier installation. While it excels in providing ample hot water for larger households or simultaneous uses, it demands a dedicated 240V supply and professional installation, similar to the Tempra 29 Plus. For buyers needing a reliable, high-capacity unit with adjustable settings, this model offers the best blend of power and control.
Pros:- Three heating chambers for high capacity
- Digital thermostat with precise control
- Self-modulating for energy efficiency
- Easy bottom water connections for installation
Cons:- Requires professional electrical installation
- High power draw, increasing operational costs
- Limited to 240V power supply
Best for: Large households or homes with high simultaneous hot water needs that have strong electrical systems.
Not ideal for: Small apartments or homes with limited electrical capacity, due to high power requirements.
- Voltage:240V
- Heating Chambers:3
- Type:Tankless
- Control:Digital thermostatic
- Installation:Bottom 3/4 inch NPT
Our verdict“This model provides excellent capacity and precise control for large households with existing electrical infrastructure.”
27kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater, Flow Rate Max 7.4 GPM, Indoor Installation, Heavy Duty for Whole House
This NOVIEEX 27kW unit stands out for its impressive 7.4 GPM flow rate, making it suitable for large households with multiple simultaneous water demands. Compared to smaller models like the Rheem RTEX-24, it offers much higher capacity but requires a dedicated electrical setup, including a 3 × 40A double-pole circuit breaker, making installation more complex. Its compact design and LED controls make it accessible for those comfortable with electrical work or willing to hire professional installers. While this model excels in performance, its high power requirement limits use to homes with robust electrical systems, which could be a hurdle for some. Tradeoff: you gain capacity and durability at the expense of more demanding installation needs.
Pros:- Supports multiple fixtures with a 7.4 GPM flow rate
- Precise temperature control with LED display
- Energy-efficient with up to 60% savings on heating costs
- Compact size for indoor installation
Cons:- Requires a dedicated 3 × 40A electrical circuit, complicating installation
- Limited to indoor use and may need professional wiring
Best for: Large households needing reliable, high-flow hot water at multiple points simultaneously
Not ideal for: Small apartments or homes with limited electrical capacity, due to its high power demands
- Power:27kW
- Voltage:240V
- Flow Rate:7.4 GPM
- Dimensions:14.13″ (W) × 15.86″ (H) × 3.18″ (D)
- Water Connection:3/4″ NPT
- Temperature Range:77°F to 140°F
- Safety Certifications:8-layer safety system
Our verdict“This unit is best for large homes with strong electrical systems that demand high capacity and reliable performance.”
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater
The Rheem RTEX-24 offers a balance between capacity and ease of setup, providing up to 5.9 GPM, making it a solid choice for small to medium households. Unlike the NOVIEEX 27kW, it requires less electrical power—just a 240V circuit—though still demanding proper wiring, which might limit some installations. Its digital thermostat allows for precise temperature adjustments, and its compact size makes it ideal for tight spaces. However, its flow rate caps at 5.9 GPM, which can be a limitation for households with multiple simultaneous hot water needs. Compared to larger units, it’s more straightforward to install but may struggle during peak demand in bigger homes. Tradeoff: you get easier installation and a smaller footprint, but at the cost of slightly reduced capacity.
Pros:- Space-saving compact design
- Digital temperature controls for precision
- No venting required simplifies installation
- Heats water only when needed for efficiency
Cons:- Limited to 5.9 GPM, which may be insufficient for large households
- Requires professional electrical installation due to high power needs
- High electrical requirements may restrict some homes
Best for: Families or small households seeking reliable hot water with simpler electrical requirements
Not ideal for: Large households with high simultaneous water demand, as it might not keep up during peak times
- Power:24kW
- Voltage:240V
- Flow Rate:5.9 GPM
- Temperature Range:80°F – 140°F
- Warranty:5-Year Leak, 1-Year Parts
- Installation:Indoor, no venting needed
Our verdict“This model is ideal for small to medium homes prioritizing straightforward setup and reliable on-demand hot water.”
18kW Tankless Electric Water Heater 240V for Whole House, Gray
The 18kW model offers a practical solution for homes that need a reliable water heater without high energy demands. With a flow rate suitable for 3-4 fixtures, it fits well in smaller households or as a supplement to existing systems. Its size and simple wiring make it appealing for those wary of complex electrical upgrades, requiring two 40-amp circuit breakers. Compared to the Rheem RTEX-24, it provides slightly less capacity but consumes less power, which can be an advantage in homes with limited electrical infrastructure. Its precise temperature control and safety features bolster confidence in its performance, but it may struggle during simultaneous usage in larger households. Tradeoff: you gain easier installation and lower power requirements at a slight reduction in flow capacity.
Pros:- Energy-efficient with up to 50% cost savings
- Compact size fits various spaces
- Precise temperature control with LED display
- Requires only two 40-amp circuit breakers
Cons:- Limited to 3-4 simultaneous usage points
- Lower flow rate compared to larger units
- Installation still requires professional electrical work
Best for: Smaller homes or apartments that need a dependable whole-house hot water system with minimal electrical upgrades
Not ideal for: Large households with multiple simultaneous hot water needs, as it may not support peak demand
- Power:18kW
- Voltage:240V
- Dimensions:15.87″ x 11.14″ x 2.87″
- Water Connection:3/4″ NPT
- Temperature Range:86°F to 131°F
- Number of Circuit Breakers:2 × 40A
Our verdict“This unit suits smaller households seeking an efficient, space-saving whole-house water heater that’s easier on electrical systems.”
How We Picked
These products were evaluated based on performance capacity, build quality, feature set, usability, and value. Priority was given to models with high flow rates, adjustable temperature controls, and certifications for safety and efficiency. We also considered user-friendly features like Wi-Fi connectivity and ease of installation. The ranking reflects a balance of power, smart technology, durability, and price, ensuring options suit a range of premium buyers seeking reliable, high-end electric tankless water heaters.Factors to Consider When Choosing Best Tankless Water Heater Electric Premium
Choosing the best electric tankless water heater involves considering several key factors that influence performance and longevity. Beyond features, understanding how capacity, efficiency, and installation impact daily use can prevent costly mistakes and ensure you select a model that truly fits your household’s hot water needs.Flow Rate and Capacity
Flow rate determines how much hot water a unit can deliver per minute, which is critical for larger households or homes with multiple fixtures running simultaneously. Selecting a model with insufficient capacity can result in cold water during peak usage, so it’s essential to estimate your peak demand accurately. Higher wattage units generally provide higher flow rates but may require more robust electrical systems, influencing installation costs.
Energy Efficiency and Power
Energy efficiency affects both utility bills and environmental impact. Look for models with good insulation, high-quality heating elements, and certifications like ETL or UL. While more powerful units deliver more hot water, they also consume more electricity, so balancing capacity with efficiency is key. Overestimating your needs can lead to unnecessary energy costs, so match the wattage to your household’s actual demand.
Smart Features and Connectivity
Wi-Fi-enabled models offer remote temperature control and maintenance alerts, adding convenience and potential energy savings. However, these features come at a premium and may require ongoing software updates or troubleshooting. Decide if smart control aligns with your tech preferences and budget, or if a simpler, more straightforward model suffices for your household’s needs.
Installation and Space Requirements
Proper installation is vital for safety and performance. Some units require dedicated electrical circuits or specific clearances, increasing setup complexity and cost. Compact models are easier to install in tight spaces but may have lower capacity. Consider your available space and electrical infrastructure when choosing a model to avoid surprises during installation.
Price and Long-Term Value
Premium models tend to have higher upfront costs but often provide better durability, efficiency, and features. Cheaper units might save money initially but could require more maintenance or replacements sooner. Focus on the overall value—investment in a high-quality, well-rated unit can result in lower operating costs and greater peace of mind over time.
Frequently Asked Questions
How do I determine the right capacity for my household?
To find the appropriate capacity, consider the number of bathrooms and fixtures, as well as peak usage times. For example, a household with multiple bathrooms may require a unit with a flow rate of 6 GPM or higher. Estimating your maximum hot water demand helps avoid cold surprises and ensures the selected heater can meet your household’s needs without overpaying for unnecessary power.
Are smart Wi-Fi features worth the extra cost?
Smart features can add convenience through remote control and maintenance alerts, potentially saving energy and preventing issues. However, they often increase the upfront price and may require ongoing software updates. If you value automation and app connectivity, investing in a Wi-Fi-enabled model makes sense; otherwise, simpler units tend to be more budget-friendly and equally reliable.
Can I install a tankless water heater myself?
While some experienced DIYers with electrical skills might handle installation, most models require professional setup due to high voltage connections and specific clearances. Improper installation can lead to safety hazards, code violations, and reduced performance. Consulting a licensed technician ensures proper installation and long-term reliability, especially for larger or more complex units.
How do I maintain my electric tankless water heater?
Regular maintenance involves flushing the unit to prevent mineral buildup, checking for leaks, and inspecting electrical connections. Many models include maintenance alerts or diagnostic features. Proper upkeep extends the lifespan of the heater and maintains efficiency. Following manufacturer instructions and scheduling annual inspections can help you avoid costly repairs or replacements later.
Is a higher wattage always better?
Not necessarily. While higher wattage units provide greater hot water output, they also require more electrical capacity and may increase energy consumption. Overestimating your need leads to higher costs without practical benefit. Conversely, undersized units can struggle to meet demand, causing inconvenience. Choose a wattage level that matches your household’s peak usage for best results.
Conclusion
For households needing maximum capacity and reliable performance, the Rheem RTEX-36 remains the best overall choice. The Electrolux 18kW is ideal for tech enthusiasts seeking smart features. Budget-conscious buyers can consider the Westinghouse models that balance capacity with affordability. Beginners or small households benefit from simpler, easier-to-install units like the Rheem RTEX-13. For those prioritizing efficiency and advanced controls, premium options like the Stiebel Eltron Tempra 29 Plus are worth the investment. Match your specific needs with these recommendations to find the best fit.Fall Picks
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