Choosing a tankless water heater electric involves balancing power, size, and cost. The best overall pick, the Stiebel Eltron Tempra 24 Trend, offers reliable performance for mid-sized households. For smaller spaces or point-of-use needs, options like the ThermoMate 4.5kW excel in affordability and simplicity. The main tradeoffs include flow rate limitations versus energy efficiency and installation complexity. Keep reading for a detailed breakdown of the top models and what makes each stand out.
Key Takeaways
- High-powered units like the APUS 27kW provide higher flow rates, suitable for larger households, but may require dedicated circuits.
- Compact and budget-friendly models such as the ThermoMate 4.5kW are ideal for small applications but often lack high flow capacity.
- WiFi-enabled options like the Westinghouse 14kW add smart control features, yet tend to come at a premium price.
- Self-modulating units, such as the 18kW Electric Tankless Water Heater, improve efficiency but may have slightly lower maximum flow rates.
- Flow rate and power output are the key factors determining whether a heater can meet household demands, especially for simultaneous usage.
| tankless water heaters electric | Power | Voltage | Flow Rate | Temperature Range |
|---|---|---|---|---|
| Stiebel Eltron Tempra 24 Trend | 24kW | 240V | — | — |
| ThermoMate 4.5kW Tankless Unde | 4.5kW | 120V | 0.26GPM-1.0GPM | 85°F – 131°F |
| 27kW Tankless Water Heater Ele | 27kW | 240V | 7.4 GPM | 77°F to 140°F |
| 14kW Tankless Electric Water H | 14kW | 240V | 3.38 GPM | 86°F – 140°F |
| 110V Tankless Electric Water H | 3000W | 110V | 0.3GPM to 0.5GPM | — |
| APUS 27kW Electric Tankless Wa | 27kW | 240V | Up to 6.5 GPM | — |
| 12KW Electric Tankless Water H | 12KW | 240V | Up to 3.3 GPM | 77-131℉ |
| Rheem 8kW Multi Fixture Tankle | 8kW | 240V | Up to 1.95 GPM | 80°F – 140°F |
| APUS 14kW Tankless Electric Wa | 14kW | 240V | Up to 3.3 GPM | 86-131°F |
| 110V Tankless Electric Water H | 3000W | 110V | 0.3-0.5 GPM | 82-131°F |
| 18kW Tankless Water Heater Ele | 18kW | 240V | 4.9 GPM | 77°F to 140°F |
| Westinghouse 14kW Tankless Ele | 14kW | 240V | Supports 3.4 GPM at 105°F | — |
| Tankless Electric Water Heater | 3000W | 110V | — | — |
| 18kW Tankless Water Heater Ele | 18kW | 240V | 4.3 GPM | — |
| 18kW Electric Tankless Water H | 18kW | 240V | — | — |
More Details on Our Top Picks
Stiebel Eltron Tempra 24 Trend Electric Tankless Water Heater, 24kW, 240V
The Stiebel Eltron Tempra 24 Trend stands out for its combination of reliable performance and space-saving design, making it ideal for whole-home hot water needs. Unlike larger models like the NOVIEEX 27kW, it offers a lower power draw while still providing continuous hot water, but it requires a substantial electrical service of 150 A, which can complicate installation. The digital temperature display and silent operation enhance user experience, and the absence of venting makes it perfect for compact spaces. However, the high electrical demand limits its suitability for older or smaller electrical systems, and installation complexity could add to overall costs. This pick makes the most sense for homeowners seeking a dependable, energy-efficient unit with minimal noise and space requirements.
Pros:- Provides unlimited on-demand hot water with consistent temperature
- Compact, space-efficient design suitable for various installations
- Silent operation and digital temperature control enhance usability
- No venting required, simplifying installation
Cons:- Requires a high electric service of 150 A, which may need electrical upgrades
- Installation can be complex and costly due to power requirements
Best for: Homeowners with modern electrical panels seeking a reliable, on-demand whole-house heater
Not ideal for: Older homes with limited electrical capacity or those unwilling to upgrade their electrical system
- Power:24kW
- Voltage:240V
- Recommended Electric Service:150 A
- Output Water Temperature:68° to 140°F
- Warranty:7-Year Leakage, 3-Year Parts
Our verdict“This model suits those needing a dependable, space-efficient heater for a whole home with modern electrical infrastructure.”
ThermoMate 4.5kW Tankless Under Sink Water Heater Electric, ETL Approved
The ThermoMate 4.5kW Under Sink Heater offers instant hot water in a compact package, making it ideal for small spaces and specific applications like sinks or RVs. Compared to larger units like the NOVIEEX 27kW, it provides a limited flow rate, suitable only for low-demand scenarios, but its self-modulating power ensures energy efficiency. Its digital touch control makes temperature adjustments straightforward, and the waterproof IP25 rating adds durability. However, its reliance on a 120V supply and hardwired installation can be restrictive for some, and it isn’t designed to handle multiple outlets simultaneously or larger household needs. This model best fits those who need a dedicated, efficient solution for a single point of use, especially in tight spaces or mobile setups.
Pros:- Provides instant, on-demand hot water for a single point of use
- Compact, space-saving design perfect for tight spots
- Digital control allows precise temperature adjustment
- Energy-efficient with self-modulating power
Cons:- Limited flow rate restricts use for multiple outlets or larger demands
- Requires hardwired installation with specific electrical requirements
Best for: RVs, small apartments, or kitchen sink installations with limited hot water demand
Not ideal for: Whole-house applications or homes with multiple simultaneous hot water needs
- Power:4.5kW
- Voltage:120V
- Flow Rate:0.26GPM-1.0GPM
- Temperature Range:85°F – 131°F
- Dimensions:10.95″ x 7.4″ x 2.52″
- Waterproof Rating:IP25
Our verdict“This unit is ideal for small-scale, point-of-use hot water needs where space and efficiency matter most.”
27kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater, Flow Rate Max 7.4 GPM, Indoor Installation
The NOVIEEX 27kW Electric Tankless Water Heater supports high flow rates up to 7.4 GPM, making it suitable for large households or multiple simultaneous fixtures. It offers precise temperature control and high efficiency, comparable to the Stiebel Eltron Tempra 24 Trend, but with a higher power capacity that demands a robust electrical setup. Its comprehensive safety features enhance reliability, yet its large size and high power consumption mean professional installation is essential, especially in homes with limited electrical capacity. This model is best suited for those who need dependable, whole-house hot water with minimal wait times and can accommodate its power needs, though upfront costs can be significant.
Pros:- Supports multiple fixtures with a high flow rate of 7.4 GPM
- Precise temperature control with LED display
- High energy efficiency with 99.8% conversion rate
- Includes safety protections for reliable operation
Cons:- High power demand necessitates professional, potentially costly installation
- Heavy and large, challenging to fit in small spaces
Best for: Large families or homes with multiple bathrooms requiring simultaneous hot water
Not ideal for: Small residences or homes with limited electrical infrastructure
- Power:27kW
- Voltage:240V
- Flow Rate:7.4 GPM
- Temperature Range:77°F to 140°F
- Maximum Current:112.5A
- Inlet Size:3/4″ NPT
Our verdict“This model is perfect for larger households needing reliable, fast hot water at multiple points simultaneously with robust safety features.”
14kW Tankless Electric Water Heater ORBEK On Demand 240V 3.38 GPM
The ORBEK 14kW Tankless Electric Water Heater offers a balanced mix of capacity and efficiency, making it a strong choice for small to medium hot water needs. It supports up to 3.38 GPM, which is suitable for two to three points of use, outperforming smaller units like the 12kW models. Its space-saving design and high efficiency—up to 60% energy savings—make installation straightforward in limited spaces. The built-in safety features and stable temperature control add reliability. However, it requires a dedicated 240V/60A circuit, and exceeding its flow rate can lead to temperature fluctuations. This makes it ideal for households or setups with moderate demand but not for larger, multi-bath scenarios.
Pros:- Supports hot water for multiple points with a flow rate of 3.38 GPM
- High efficiency with significant energy savings
- Compact, space-saving design for easy installation
- Built-in safety features for dependable operation
Cons:- Requires a 240V/60A circuit, which may need electrical upgrades
- Flow rate limits its ability to serve many fixtures simultaneously
Best for: Small homes, apartments, or side installations where moderate hot water demand exists
Not ideal for: Large households or high-demand applications with multiple simultaneous fixtures
- Power:14kW
- Voltage:240V
- Flow Rate:3.38 GPM
- Temperature Range:86°F – 140°F
- Dimensions:14.2″H x 9.5″L x 3.1″W
Our verdict“This model fits well in small-scale applications where moderate hot water demand and space efficiency are priorities.”
110V Tankless Electric Water Heater, 3000W, Instant Hot Water with Digital Display for Kitchen and Bathroom
The 110V 3000W Tankless Electric Water Heater delivers hot water efficiently for small applications like kitchen sinks, bathrooms, or RVs. Its compact, wall-mounted design makes installation straightforward, especially where standard electrical wiring is available. While it excels in providing instant hot water at flow rates of 0.3 to 0.5 GPM, it’s limited for use in showers or high-demand scenarios, as flow rates are insufficient for larger fixtures. Its multiple safety protections, including leakage and overheat prevention, add peace of mind. Compared to 240V models like the ORBEK or NOVIEEX, it has lower power, restricting its capacity, but it shines in portable or space-constrained environments where minimal hot water is needed.
Pros:- Instant hot water with high thermal efficiency
- Space-efficient, wall-mounted design
- Multiple safety protections enhance reliability
- Easy to install with standard connections
Cons:- Flow rate too low for showers or high-demand fixtures
- Limited to vertical wall mounting, restricting placement options
Best for: RVs, small apartments, or secondary hot water points where space and power are limited
Not ideal for: Whole-house heating or high-flow, multi-point applications
- Power:3000W
- Voltage:110V
- Water Temperature Increase:82°F to 131°F
- Flow Rate:0.3GPM to 0.5GPM
- Protection Features:IPX4 waterproof, leakage, dry boil, overheat
Our verdict“This heater is perfect for small-scale, low-flow needs in mobile or compact environments where space and power are limited.”
APUS 27kW Electric Tankless Water Heater, 240V, Up to 6.5 GPM, 3s Instant
This APUS 27kW model stands out for its ability to deliver high-flow hot water across multiple fixtures, making it a strong choice for larger households needing reliable, simultaneous hot water. Compared with the Rheem 8kW unit, it offers a significantly higher flow rate and digital controls, though it demands a dedicated 240V electrical setup and professional installation. The self-modulating technology ensures energy efficiency, reducing operating costs despite its high power draw. Its compact, wall-mounted design simplifies installation in tight spaces, but performance can vary depending on inlet water temperature and household demand. For those seeking a true whole-home solution, this model balances capacity with efficiency, provided the electrical infrastructure supports it.
Pros:- Provides high-flow hot water suitable for whole-home use
- Digital control with precise temperature adjustment
- Energy-efficient self-modulating technology reduces electricity use
- Compact wall-mounted design saves space
Cons:- Requires professional installation and specific electrical setup
- Flow rate varies with inlet water temperature and household demand
Best for: Homeowners with larger households who need reliable, simultaneous hot water for multiple fixtures
Not ideal for: Small apartments or DIYers without dedicated high-voltage electrical wiring, as installation complexity is high
- Power:27kW
- Voltage:240V
- Flow Rate:Up to 6.5 GPM
- Dimensions:17.7 × 11.4 × 3.5 inches
- Water Connections:3/4-inch NPT
- Technology:Self-modulating
Our verdict“This model makes the most sense for larger homes with existing high-voltage electrical capacity and a need for multiple simultaneous hot water outlets.”
12KW Electric Tankless Water Heater 240V, Self Modulating White Unit
Compared with the larger APUS model, this 12kW heater is better suited for small apartments, single sinks, or handwashing stations, offering instant hot water without the need for preheating. Its compact size and simple digital control make it appealing for DIYers, but the limited flow rate restricts its use to low-demand scenarios. While it provides reliable on-demand hot water at a modest power level, it can’t support multiple outlets simultaneously, unlike the APUS. This unit’s self-modulating feature enhances energy efficiency, but its flow rate may fall short in larger households or during peak demand. For those with limited space and modest hot water needs, this heater balances ease of installation with performance.
Pros:- Compact and space-saving design
- Provides instant hot water without preheating
- Digital controls for easy temperature adjustment
- Energy-efficient self-modulating technology
Cons:- Limited flow rate, not suitable for multiple fixtures
- May require professional installation for electrical compatibility
Best for: Singles or small households needing point-of-use hot water at sinks or small bathrooms
Not ideal for: Large families or homes with multiple bathrooms, as flow rate is too limited for simultaneous use
- Power:12KW
- Voltage:240V
- Temperature Range:77-131℉
- Color:White
- Flow Rate:Up to 3.3 GPM
- Technology:Self-modulating
Our verdict“Ideal for small, low-demand applications where space and ease of installation are priorities, but not for whole-home use.”
Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V
Compared with the APUS 27kW unit, the Rheem 8kW model is much smaller and better suited to small-scale applications like a single sink or small bathroom, offering reliable hot water for limited demand. Its digital thermostatic controls allow precise settings, but the lower power limits its flow rate to about 1.95 GPM, making it unsuitable for larger households or multiple simultaneous outlets. Unlike the larger APUS unit, it’s easier to install in tight spaces and requires less electrical infrastructure, yet its capacity restricts its use to single fixtures or small point-of-use scenarios. This makes it a good choice for those looking for a space-efficient, on-demand hot water solution for limited applications.
Pros:- Space-saving compact design
- Digital temperature controls for precise settings
- Reliable on-demand hot water
- Energy-efficient operation
Cons:- Limited flow rate, not suitable for multiple outlets
- Requires professional installation and specific electrical wiring
Best for: Small households or individual fixtures needing reliable hot water with minimal installation fuss
Not ideal for: Large families or multiple fixtures, due to its limited flow capacity and power
- Power:8kW
- Voltage:240V
- Flow Rate:Up to 1.95 GPM
- Temperature Range:80°F – 140°F
- Warranty:5-Year Leak, 1-Year Parts
- Technology:Digital thermostatic control
Our verdict“Best suited for small-scale, space-conscious applications where limited flow is acceptable.”
APUS 14kW Tankless Electric Water Heater, 240V, Up to 3.3 GPM
This 14kW APUS model offers a good balance between size and capacity, making it ideal for point-of-use applications like a single shower or sink. Compared with the 27kW model, it delivers a more modest flow rate, but with high thermal efficiency and precise digital temperature control, it ensures reliable hot water for light demand scenarios. Its wall-mounted design makes it easy to install in small spaces, but it isn’t suitable for larger households or multiple simultaneous outlets. For those seeking a compact, energy-efficient heater for specific fixtures, this model provides dependable performance without the complexity of high-voltage electrical requirements.
Pros:- Compact and space-efficient
- High thermal efficiency
- Precise digital temperature control
- Ideal for point-of-use applications
Cons:- Flow rate limited for larger household needs
- Requires professional electrical installation
Best for: Single fixture setups such as a bathroom sink or small shower in apartments or small homes
Not ideal for: Households with multiple bathrooms or high simultaneous demand, as flow rate is limited
- Power:14kW
- Voltage:240V
- Flow Rate:Up to 3.3 GPM
- Temperature Range:86-131°F
- Dimensions:13.7 x 11.42 x 3.54 inches
- Efficiency:99.8%
Our verdict“Perfect for light-demand, space-constrained applications where reliable hot water is needed for a single fixture.”
110V Tankless Electric Water Heater, 3000W, Instant Hot Water with Digital Display
This 110V, 3000W heater is designed for small-scale applications like kitchen sinks, outdoor faucets, or bathrooms with low flow needs. Its high energy efficiency and safety features, such as waterproofing and leakage-proof design, make it suitable for outdoor or semi-outdoor use, unlike larger 240V models. The flow rate of 0.3 to 0.5 GPM limits its use to point-of-use scenarios, and it’s not suitable for showers or high-demand fixtures. Compared with the 14kW APUS model, this unit is even more compact and easier to install but sacrifices capacity for smaller, specific applications. It’s an excellent choice where space is limited, and demand is light.
Pros:- Instant heating with precise temperature control
- Compact wall-mounted design
- High thermal efficiency of 98%
- Safety protections for reliable outdoor operation
Cons:- Flow rate too low for shower use
- Horizontal installation not permitted
Best for: Outdoor kitchens, small bathrooms, or outdoor shower setups with low water flow requirements
Not ideal for: Main bathrooms or household-wide hot water needs, due to flow and power limitations
- Power:3000W
- Voltage:110V
- Temperature Range:82-131°F
- Flow Rate:0.3-0.5 GPM
- Material:Stainless steel and ABS
- Protection:IPX4 waterproof
Our verdict“Best for small, specific applications where space and safety are primary concerns, not for whole-house use.”
18kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater, Flow Rate Max 4.9 GPM, Supply for 2-3 Points, Indoor Installation
The NOVIEEX 18kW model earns its place as the best overall choice for small to medium-sized households needing reliable, on-demand hot water. Its compact, wall-mounted design saves space, while the high flow rate of 4.9 GPM supports multiple fixtures simultaneously, making it a solid upgrade over smaller units like the 14kW options. The precise LED temperature control and high thermal efficiency help reduce energy costs, but the electrical demands mean professional installation is a must. Compared to lower-watt models, this unit offers higher capacity, yet it’s limited to homes with suitable electrical wiring. It’s ideal for those who want a balance of performance, safety, and space-saving design, but unsuitable for larger households or homes without dedicated electrical capacity.
Pros:- Space-saving wall-mount design
- Supports multiple fixtures simultaneously
- Precise temperature control with LED display
- High thermal efficiency reduces energy costs
Cons:- Requires professional installation due to electrical demands
- Limited capacity for larger households
- Specific wiring and breaker setup necessary
Best for: Families or small households with existing 240V electrical setups seeking reliable hot water for 2-3 fixtures.
Not ideal for: Large households or homes without the necessary electrical infrastructure, as installation costs and complexity can be prohibitive.
- Power:18kW
- Voltage:240V
- Flow Rate:4.9 GPM
- Temperature Range:77°F to 140°F
- Dimensions:11.14″ x 15.86″ x 3.18″
- Maximum Current:75A
Our verdict“This unit suits small to medium homes where space is limited but reliable, high-capacity hot water is needed, with the caveat of requiring expert installation.”
Westinghouse 14kW Tankless Electric Water Heater, 240V, WiFi, ETL Certified, Gray
The Westinghouse 14kW tankless heater is tailored for users who value smart features and easy maintenance. Its WiFi and voice control capabilities make adjusting temperature and monitoring performance straightforward, especially compared to simpler units like the 3000W digital display model. The compact design fits well in tight spaces, and its safety certifications add peace of mind. However, the 3.4 GPM flow rate at 105°F limits its use to small households or point-of-use applications, and the need for a dedicated 60A double-pole breaker complicates installation. This model is best suited for tech-savvy homeowners seeking modern controls, but less so for larger households or those with limited electrical capacity.
Pros:- Smart WiFi and voice control
- Supports quick hot water delivery in 3 seconds
- Compact and space-efficient design
- Durable with anti-scale technology
Cons:- Installation requires a dedicated 60A breaker
- Flow rate limited to 3.4 GPM at 105°F
- Can be complex for non-expert DIYers
Best for: Tech-oriented homeowners who want remote control and monitoring with reliable instant hot water for small-scale needs.
Not ideal for: Large families or homes demanding high flow rates, as the 3.4 GPM limit restricts simultaneous hot water use significantly.
- Power:14kW
- Voltage:240V
- Flow Rate:Supports 3.4 GPM at 105°F
- Certifications:ETL
- Protection Features:Leakage, overheat, dry-fire, over-voltage
- Dimensions:12.59″H x 9.56″W x 3.28″D
Our verdict“Ideal for small households that prioritize smart features and remote control, but not suited for high-demand scenarios.”
Tankless Electric Water Heater, 3000W, 110V, Digital Display
This 3000W, 110V model makes a strong case for small-scale applications like kitchens, RVs, or cabins. Its digital display allows precise temperature adjustments, and safety features like dry-burning protection and waterproofing boost reliability. Compared to higher wattage units like the NOVIEEX 18kW, this is far less suitable for shower use or larger demands but excels where space is tight and only low flow rate hot water is needed. Its limited flow rate of 0.3-0.5 GPM confines it to single fixtures, making it a good fit for sink or small appliance use but not for whole-house needs. Easy to install with standard wiring, it’s ideal for those who need instant hot water in a tiny footprint, but not for high-volume scenarios.
Pros:- Very compact and space-efficient
- Digital temperature control
- Multiple safety protections
- Easy to install with standard wiring
Cons:- Not suitable for shower use
- Very limited flow rate
- Requires professional wiring and circuit breaker
Best for: Homeowners or travelers needing instant hot water for sinks or small appliances in tight spaces.
Not ideal for: Bathrooms or households requiring shower hot water, due to its very limited flow rate and capacity.
- Power:3000W
- Voltage:110V
- Temperature Rise:82°F to 131°F
- Water Flow Rate:0.3GPM to 0.5GPM
- Protection Features:IPX4 waterproof, leakage, dry-burning, over-temperature
- Installation:Vertical only
Our verdict“Best for small-scale, low-flow applications where space and power are limited, but not for whole-house or shower needs.”
18kW Tankless Water Heater Electric 240V, Self-Modulating
This self-modulating 18kW model is designed for point-of-use applications, such as near showers or laundry areas. Its smart energy regulation helps reduce waste and operating costs compared to fixed-power units like the Westinghouse 14kW. The 4.3 GPM flow rate supports multiple fixtures, making it suitable for small to medium demands. Its safety features, including leakage and high-temperature protections, enhance reliability. Compared to the more feature-rich WiFi models, this unit emphasizes straightforward performance and durability, but it requires specific wiring (40A double-pole breaker) and professional installation. It’s a good fit where space is limited and hot water is needed instantly without extensive setup.
Pros:- Provides instant, endless hot water
- Energy-efficient with smart regulation
- Safe with multiple protections
- Compact and space-efficient
Cons:- Requires specific electrical wiring (40A breaker)
- Limited to point-of-use applications
- Installation may need professional help
Best for: Homeowners seeking a reliable, point-of-use hot water solution near showers or washing machines with energy efficiency in mind.
Not ideal for: Large households or whole-house applications, as the flow rate and capacity are more suited to localized use.
- Power:18kW
- Voltage:240V
- Flow Rate:4.3 GPM
- Protection Features:Leakage, dry heating, high temp, auto stop
- Fittings:3/4″ NPT
- Circuit Requirements:40A double pole breaker
Our verdict“This model suits localized hot water needs with energy savings, but isn’t designed for whole-house applications.”
18kW Electric Tankless Water Heater 240V WiFi
This 18kW unit combines high capacity with WiFi control, making it ideal for households needing hot water for 2-3 bathrooms. The self-modulating technology ensures energy efficiency, and the 4.3 GPM output supports multiple fixtures simultaneously, similar to the self-modulating model. Its space-saving wall-mount design and remote control capabilities make it especially appealing for modern homes. Compared to simpler models like the 3000W digital display heater, this offers more capacity and smart features, but the electrical setup—requiring two 40-amp breakers and high-quality wiring—can be a barrier for some installations. It’s best suited for homeowners with existing electrical infrastructure ready for upgrade, aiming for whole-house hot water without bulky tanks.
Pros:- Continuous hot water without preheating
- WiFi control for remote adjustments
- Space-efficient wall mount
- Energy-efficient self-modulating tech
Cons:- Requires professional installation with heavy electrical work
- Limited hot water output for very large households
- Electrical setup can be complex
Best for: Families needing continuous hot water for multiple bathrooms with remote management and energy efficiency.
Not ideal for: Properties without adequate electrical infrastructure, or for those seeking an inexpensive or simple solution.
- Power:18kW
- Voltage:240V
- Maximum Hot Water Output:4.3 GPM
- Dimensions:11.1″ W x 19.2″ H x 4″ D
- Water Connection:3/4″ NPT
- Wiring:2 x 40 Amp DP breakers
Our verdict“This model is perfect for larger homes demanding reliable, remote-controlled hot water, provided electrical capacity is available.”
