Choosing the best tankless water heater electric depends on your home’s hot water demands, budget, and installation space. The Stiebel Eltron Tempra 29 Plus stands out for its reliable performance and advanced technology, making it a top overall pick. For those seeking a budget-friendly yet effective option, the Rheem RTEX-27 offers solid capacity at a lower price. Meanwhile, the Westinghouse 14kW appeals to users wanting WiFi control and smart features. Every model has tradeoffs—higher capacity units can be pricier and more complex to install, while smaller units may struggle with larger households. Continue reading for a detailed breakdown of these options and more to find the best fit for your home.
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Key Takeaways
- Higher wattage models generally provide greater flow rates but come with increased installation complexity and cost.
- Smart features like WiFi can add convenience but may not be necessary for all users and can increase the price.
- Size and capacity need careful matching to household hot water needs to avoid underperformance or overspending.
- Build quality and warranty support are key indicators of long-term reliability and peace of mind.
- Price varies significantly, with premium models offering advanced features and higher durability, while budget options focus on basic performance.
| Stiebel Eltron Tempra 29 Plus Electric Tankless Water Heater, 28.8kW, 240V |  | Best Overall for Whole-House Efficiency and Customization | Power: 28.8kW | Voltage: 240V | Temperature presets: 2 | VIEW LATEST PRICE | See Our Full Breakdown |
| APUS 27kW Electric Tankless Water Heater, 240V, Up to 6.5 GPM, 3s Instant |  | Best for Multi-Point Hot Water with Precise Control | Power: 27kW | Voltage: 240V | Flow Rate: Up to 6.5 GPM | VIEW LATEST PRICE | See Our Full Breakdown |
| 18kW Tankless Electric Water Heater 240V for Whole House, Gray |  | Best for Small to Medium Homes with Moderate Hot Water Needs | Power: 18kW | Voltage: 240V | Dimensions: 15.87″ x 11.14″ x 2.87″ | VIEW LATEST PRICE | See Our Full Breakdown |
| Rheem RTEX-27 240V Tankless Water Heater |  | Best for Precise Temperature Control and Easy Maintenance | Voltage: 240V | Heating Chambers: 3 | Temperature Control: Digital with LED display | VIEW LATEST PRICE | See Our Full Breakdown |
| 18kW Electric Tankless Water Heater 240V WiFi Certified |  | Best for Remote Control and Energy Savings in Moderate Homes | Power: 18kW | Voltage: 240V | Maximum flow rate: 4.3 gallons per minute | VIEW LATEST PRICE | See Our Full Breakdown |
| Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V |  | Best Compact for Space-Conscious Installations | Power: 8kW | Voltage: 240V | Flow Rate: up to 1.95 GPM | VIEW LATEST PRICE | See Our Full Breakdown |
| Westinghouse 14kW Tankless Electric Water Heater, 240V, WiFi, ETL Certified, Gray |  | Best Smart Control and Versatility | Power: 14kW | Voltage: 240V | Flow Rate: 3.4 GPM at 62°F inlet | VIEW LATEST PRICE | See Our Full Breakdown |
| 18kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater |  | Best High Power for Medium Households | Power: 18kW | Voltage: 240V | Flow Rate: 4.9 GPM | VIEW LATEST PRICE | See Our Full Breakdown |
| tankless water heater electric | Voltage | Power | Dimensions | Flow Rate |
|---|---|---|---|---|
| Stiebel Eltron Tempra 29 Plus | 240V | 28.8kW | — | — |
| APUS 27kW Electric Tankless Wa | 240V | 27kW | 17.7 × 11.4 × 3.5 inches | Up to 6.5 GPM |
| 18kW Tankless Electric Water H | 240V | 18kW | 15.87" x 11.14" x 2.87" | — |
| Rheem RTEX-27 240V Tankless Wa | 240V | — | — | — |
| 18kW Electric Tankless Water H | 240V | 18kW | 11.1" W x 19.2" H x 4" D | — |
| Rheem 8kW Multi Fixture Tankle | 240V | 8kW | — | up to 1.95 GPM |
| Westinghouse 14kW Tankless Ele | 240V | 14kW | 12.59" H x 9.56" W x 3.28" D | 3.4 GPM at 62°F inlet |
| 18kW Tankless Water Heater Ele | 240V | 18kW | 11.14" W × 15.86" H × 3.18" D | 4.9 GPM |
More Details on Our Top Picks
Stiebel Eltron Tempra 29 Plus Electric Tankless Water Heater, 28.8kW, 240V
The Stiebel Eltron Tempra 29 Plus stands out as the best option for households demanding continuous hot water without sacrificing space. Its sleek design requires no venting, ideal for modern homes, yet it demands a significant electrical setup, including three dedicated 40 amp breakers and a minimum 200 amp service—making installation complex and potentially costly. Compared with smaller units like the 18kW model, it offers higher capacity for larger homes but at the expense of electrical wiring complexity. This model’s two temperature memory presets add convenience, but the high electrical requirements mean it’s best suited for new constructions or major upgrades. Best for large households or homes with high hot water demands who can accommodate the electrical needs.
Pros:- Provides unlimited on-demand hot water for entire homes
- Space-efficient, sleek design suitable for modern interiors
- Includes two temperature memory presets for personalized comfort
Cons:- Requires complex electrical wiring and dedicated breakers
- Needs a high electrical capacity (minimum 200 amps), making installation challenging
Best for: Large households needing reliable, continuous hot water with space-saving installation
Not ideal for: Small apartments or homes with limited electrical capacity due to its high wiring requirements
- Power:28.8kW
- Voltage:240V
- Temperature presets:2
- Wiring:3 dedicated 40 amp breakers with 8 gauge copper wiring
- Installation requirements:Minimum 200 amp total service to residence
Our verdict“This model suits larger homes with robust electrical systems that prioritize capacity and space-saving design.”
APUS 27kW Electric Tankless Water Heater, 240V, Up to 6.5 GPM, 3s Instant
The APUS 27kW heater excels at delivering hot water to multiple fixtures simultaneously thanks to its 6.5 GPM flow rate, making it ideal for busy households. Its digital temperature control and self-modulating technology optimize energy use, outperforming simpler units like the 18kW model which may struggle with higher demands. The compact wall-mounted design makes installation straightforward in indoor spaces, but it requires a professional electrical setup, including a dedicated 240V circuit. While it offers excellent flow and precise control, its high initial cost and specific voltage needs could deter smaller households or those with limited electrical infrastructure. Best suited for medium-sized homes or shared living spaces with multiple simultaneous hot water needs.
Pros:- Handles multiple fixtures at once with high flow rate
- Digital control allows precise temperature adjustment
- Energy-efficient self-modulating technology reduces electricity consumption
- Space-saving indoor wall-mounted design
Cons:- Requires professional installation and proper electrical setup
- Higher initial cost compared to smaller units
Best for: Families with multiple bathrooms or high simultaneous hot water demands
Not ideal for: Small apartments or homes with limited electrical capacity due to its high power requirements
- Power:27kW
- Voltage:240V
- Flow Rate:Up to 6.5 GPM
- Temperature Range:86°F–140°F
- Dimensions:17.7 × 11.4 × 3.5 inches
- Water Connection:3/4-inch NPT
Our verdict“This heater makes the most sense for households with multiple simultaneous hot water needs and adequate electrical infrastructure.”
18kW Tankless Electric Water Heater 240V for Whole House, Gray
The 18kW tankless heater offers a reliable solution for homes with modest hot water demands, providing instant heat with 99.8% efficiency. It’s less demanding on electrical wiring than larger models, requiring only two 40-amp breakers, but this limits its capacity to serve only 3-4 outlets simultaneously. Compared to the Tempra 29 Plus, it’s easier to install and more affordable, yet it’s less suitable for larger households or those with high simultaneous hot water needs. Its safety features, including leakage and overheating protections, add peace of mind. This unit is perfect for small families or apartments but may fall short in bigger homes. Best for homes where hot water demand is moderate and electrical capacity is limited.
Pros:- Energy-efficient with minimal standby power
- Provides instant hot water for multiple outlets
- Easy to install with lower electrical requirements
Cons:- Limited to 3-4 usage points simultaneously
- Less suitable for large households or high demand scenarios
Best for: Small households or apartments with 1-2 bathrooms
Not ideal for: Large families or homes with multiple bathrooms requiring simultaneous hot water
- 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
- Efficiency:99.8%
Our verdict“This unit is ideal for small homes or apartments where space and electrical capacity are priorities.”
Rheem RTEX-27 240V Tankless Water Heater
The Rheem RTEX-27 offers precise digital temperature control with an LED display, making it ideal for users who want exact hot water settings. Its three copper immersion heating chambers are durable and easy to replace, simplifying maintenance compared to units like the APUS 27kW which has self-modulating technology but less focus on user control. Installation requires a professional due to electrical complexity, and its capacity may be limited for larger households. While it lacks the advanced smart features of the WiFi-enabled model, it compensates with straightforward operation and durability. It’s a dependable choice for homeowners prioritizing control and ease of service. Best for users valuing precise temperature control and simple maintenance.
Pros:- Digital temperature control with LED display
- Durable copper heating elements
- Easy to install and maintain
Cons:- Requires professional electrical installation
- Limited heating chambers may affect hot water capacity
Best for: Homeowners who prioritize exact temperature settings and straightforward serviceability
Not ideal for: Large households or those seeking WiFi connectivity for remote control
- Voltage:240V
- Heating Chambers:3
- Temperature Control:Digital with LED display
- Water Connections:Bottom 3/4 inch NPT
- Heating Elements:Copper immersion
Our verdict“This model suits users who want precise control and reliable performance with easier maintenance, but not the highest flow capacity.”
18kW Electric Tankless Water Heater 240V WiFi Certified
The WiFi-enabled 18kW heater combines energy efficiency with modern convenience, featuring self-modulating technology that can save up to 99% on energy bills. Its 4.3 GPM flow rate makes it suitable for homes with 2-3 bathrooms in milder climates, similar to the APUS 27kW model, but with added remote control capabilities. Its safety features—leakage, overheat, and dry-fire protections—add to its reliability, and the compact size fits well in tight spaces. However, the need for professional installation and specific electrical wiring (two 40-amp breakers) limits its appeal for smaller or older homes. It’s best suited for tech-savvy homeowners seeking control via smartphone and energy efficiency. Ideal for moderate-sized homes in mild climates that value modern features.
Pros:- WiFi control for remote temperature adjustment
- Energy-saving self-modulating technology
- Space-saving wall-mounted design
- Includes safety protections and 2-year warranty
Cons:- Requires professional installation and specific electrical setup
- Maximum flow rate may not suffice for very large households
Best for: Tech-savvy homeowners seeking remote control and energy savings
Not ideal for: Homes with electrical limitations or in colder climates needing higher flow rates
- Power:18kW
- Voltage:240V
- Maximum flow rate:4.3 gallons per minute
- Dimensions:11.1″ W x 19.2″ H x 4″ D
- Amperage:75A
- Safety certifications:ETL Certified
Our verdict“This heater is perfect for homes in moderate climates where remote control and energy efficiency are priorities, but less suitable for larger households or colder regions.”
Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V
This Rheem model stands out for its space-saving design, making it ideal for small apartments or locations with limited room. Compared to larger units like the 18kW NOVIEEX, it offers a lower power capacity which restricts flow rate, but excels in efficiency and simplicity for single or dual fixture setups. Its digital temperature control enhances user convenience, although professional installation is essential due to specific wiring needs. It’s a solid choice for those who prioritize a discreet footprint and energy savings over high flow capacity or multi-point use.
Pros:- Space-efficient and compact design
- Energy-efficient operation by heating water only when needed
- Digital thermostatic temperature controls
Cons:- Requires professional installation with specific wiring
- Limited flow rate suitable mainly for 1-2 fixtures
Best for: Single-family dwellers or small apartments needing reliable hot water for 1-2 fixtures with limited space
Not ideal for: Large households or high-demand applications where multiple fixtures run simultaneously, due to its limited flow rate
- Power:8kW
- Voltage:240V
- Flow Rate:up to 1.95 GPM
- Temperature Range:80°F – 140°F
- Warranty:5-year leak, 1-year parts
Our verdict“This model is best suited for small spaces that need reliable, on-demand hot water without high flow demands.”
Westinghouse 14kW Tankless Electric Water Heater, 240V, WiFi, ETL Certified, Gray
The Westinghouse 14kW unit offers a significant step up in power, supporting multiple outlets with a flow rate of 3.4 GPM, making it suitable for small to medium households. Its WiFi connectivity and compatibility with Alexa and Google Home set it apart from the Rheem 8kW, providing remote control and advanced safety features. Installation requires a dedicated 60A breaker and some electrical know-how, which could challenge less experienced users. This model strikes a balance between power and smart technology, perfect for those who value convenience and integration in their setup.
Pros:- Supports multiple fixtures with 3.4 GPM flow rate
- Smart WiFi control with voice compatibility
- Compact size suitable for various spaces
- Enhanced safety features including leak and overheat protection
Cons:- Requires dedicated 60A double-pole breaker and specific wiring
- Installation can be complex for DIYers
- Inlet filters need cleaning every 6 months
Best for: Homeowners seeking smart features and moderate flow capacity for 2-3 fixtures
Not ideal for: Homes with very high hot water demands or where electrical wiring upgrades are impractical
- Power:14kW
- Voltage:240V
- Flow Rate:3.4 GPM at 62°F inlet
- Dimensions:12.59″ H x 9.56″ W x 3.28″ D
- Certifications:ETL
- Protection Features:Leakage, overheat, dry-fire, over-voltage
Our verdict“This model caters well to tech-savvy users wanting reliable hot water with remote control features in a compact package.”
18kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater
The NOVIEEX 18kW model delivers a high flow rate of 4.9 GPM, making it well-suited for small to medium households with 2-3 fixtures. Its quick heating and precise temperature control with an LED display provide a seamless user experience. The high power capacity ensures hot water availability even during simultaneous use, but this also means it requires a dedicated, robust electrical connection and professional installation, which could increase up-front costs. It’s an excellent choice for those needing substantial hot water volume without moving into whole-house tankless territory.
Pros:- High power and flow rate suitable for several fixtures
- Precise temperature control with LED display
- High thermal efficiency minimizes energy costs
- Multiple safety protections for peace of mind
Cons:- Requires professional electrical installation
- Higher initial setup cost due to power needs
- Limited to small- to medium-sized households
Best for: Families or small businesses that need reliable, high-flow hot water for multiple fixtures
Not ideal for: Very large households or properties where electrical upgrades are impossible or cost-prohibitive
- Power:18kW
- Voltage:240V
- Flow Rate:4.9 GPM
- Dimensions:11.14″ W × 15.86″ H × 3.18″ D
- Water Connection:3/4″ NPT
- Temperature Range:77°F to 140°F
- Efficiency:99.8%
Our verdict“This model is ideal for households that demand high hot water flow with quick response times and reliable performance.”
How We Picked
The products in this roundup were evaluated based on performance, ease of installation, durability, and value for money. We prioritized units with sufficient wattage to meet typical household demands, and considered user-friendly features like digital controls and WiFi connectivity. Additionally, reliability and manufacturer reputation played a key role, along with warranty coverage. Our ranking reflects a balance between capacity, features, and cost, aiming to recommend models suited for different budgets and needs without sacrificing quality.Factors to Consider When Choosing Best Tankless Water Heater Electric
When selecting the best electric tankless water heater, it’s important to consider several factors that impact performance and suitability. Proper sizing ensures you get enough hot water without overspending on unnecessary capacity. Ease of installation can vary, especially with higher wattage units that may require professional electrical work. Features like digital controls and WiFi connectivity add convenience but come at a higher price point. Additionally, filter maintenance, durability, and warranty support influence the long-term value of your investment. Understanding these factors helps avoid common pitfalls and ensures you choose a model that fits your household perfectly.Capacity and Flow Rate
Matching the water heater’s capacity to your household’s needs is essential. Larger households or homes with multiple bathrooms typically require units with higher flow rates, measured in gallons per minute (GPM). Choosing a unit with too low a flow rate will result in insufficient hot water during peak usage, while an oversized model can lead to unnecessary expense and higher energy costs. Consider your peak hot water demand when selecting wattage and flow capacity to ensure reliable performance without overspending.
Size and Installation Requirements
Electric tankless heaters can vary significantly in size and installation complexity. Higher wattage models often demand dedicated circuits and may need professional electrical upgrades, adding to installation costs. Smaller units are easier to install and may fit in tighter spaces, making them ideal for apartments or small homes. Always assess your available electrical capacity and space constraints before purchasing, and consider consulting an electrician to confirm compatibility.
Features and Connectivity
Modern models often include features like digital displays, temperature controls, and WiFi connectivity. These add convenience by enabling remote adjustments and monitoring, which can enhance user experience. However, such features typically come at a premium and may not be necessary for every user. Prioritize features based on your comfort with technology and budget, ensuring you don’t pay extra for capabilities you won’t use.
Build Quality and Warranty
Durability depends on build quality, materials, and manufacturer reputation. Look for units with corrosion-resistant components and solid construction, especially if your water supply contains minerals. A strong warranty indicates confidence from the manufacturer and can save money on repairs or replacements. Consider brands with a history of good customer support to avoid headaches down the line.
Cost and Long-Term Value
While budget models may seem attractive initially, they could lead to higher operating costs or shorter lifespans. Conversely, investing in a premium unit often provides better efficiency, advanced features, and longer durability. Balance your upfront budget with expected longevity and performance. Remember, sometimes paying more upfront results in savings over the lifespan of the unit through lower energy bills and fewer repairs.
Frequently Asked Questions
Can I install an electric tankless water heater myself?
Installing an electric tankless water heater often requires electrical expertise due to high voltage and amperage demands. While some experienced DIYers may handle basic setups, most installations should be performed by licensed electricians to ensure safety and compliance with local codes. Proper wiring, circuit breaker capacity, and clearance are critical factors that influence performance and safety. Attempting installation without proper knowledge can lead to electrical hazards or voided warranties.
How much hot water can a typical electric tankless heater supply at once?
The flow rate varies widely among models, generally ranging from 3 to 6 GPM depending on wattage and temperature rise needed. Smaller units may only serve one point of use, such as a sink or shower, while larger models can supply multiple fixtures simultaneously. Always match the unit’s capacity to your household’s peak hot water demand to avoid running out of hot water during busy times.
Are smart features worth paying extra for in an electric tankless water heater?
Smart features like WiFi connectivity can enhance convenience, allowing remote temperature adjustments and usage monitoring. However, they also increase the initial cost and complexity. If you prefer straightforward operation and don’t plan to use remote controls, a basic model might suffice. For tech-savvy users or those keen on energy management, the added features can provide valuable control and insight over time.
What maintenance does an electric tankless water heater require?
Regular maintenance involves flushing the unit periodically to prevent mineral buildup, especially if you have hard water. Checking and replacing filters or screens, if applicable, can also prolong lifespan. Many models include self-diagnostic features or alerts for maintenance needs. Proper upkeep ensures consistent performance and extends the life of the unit, ultimately saving money on repairs or replacements.
Is a higher wattage unit always better for my household?
Not necessarily. While higher wattage units provide greater flow rates and capacity, they also require more power and more complex installation. Oversized units can lead to unnecessary energy consumption and higher upfront costs. It’s better to size your unit based on your actual hot water needs—an undersized unit might struggle during peak times, but an oversized one could waste energy and money. Careful assessment of your household demand is key.
Conclusion
For most households, the Stiebel Eltron Tempra 29 Plus offers the best balance of performance, reliability, and features, making it the ideal choice for those seeking overall excellence. Budget-conscious buyers will appreciate the Rheem RTEX-27 for its solid capacity at a lower price point, while tech enthusiasts should consider the Westinghouse 14kW for its WiFi capabilities. Beginners or smaller households can opt for smaller units like the Rheem 8kW Multi Fixture for simplicity and ease of installation. Ultimately, your choice should align with your hot water needs, budget, and desired features—this guide helps you match the right model to your household profile.
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