Imagine stepping into a shower that never runs cold, no matter how long you linger. Electric tankless water heaters deliver hot water on demand, eliminating the standby energy losses of traditional tanks and freeing up valuable floor space. Whether you live in a compact apartment or a busy family home, the right unit can transform your daily routine.
This guide breaks down nine of the best electric tankless water heaters on the market, from compact 13kW point-of-use models to heavy-duty 27kW whole-house systems. We’ll help you match your household’s hot water demand, electrical capacity, and budget to the perfect unit, so you can enjoy endless showers and lower energy bills.
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Rheem 18kW 240V Tankless Electric Water Heater, Gray
Best forPrecise temperature control
- Accurate digital temperature control
- Self-modulating power saves energy
ConsiderRequires dedicated 60A breaker
18kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heat…
Best forMedium home multi-point use
- High 4.9 GPM flow rate
- Anti-scald constant temperature
ConsiderIndoor installation only
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Best forLarger households high demand
- High 5.9 GPM flow rate
- Simple dial temperature control
ConsiderRequires 100A dedicated circuit
27kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heat…
Best forWhole house heavy duty
- Massive 7.4 GPM flow rate
- Smart temperature lock
ConsiderRequires 125A dedicated circuit
APUS 27kW Electric Tankless Water Heater, 240V, Up to 6.5 GPM, 3s Instant
Best forBusy homes with memory settings
- Memory function recalls settings
- 1°F temperature adjustment
ConsiderRequires 125A dedicated circuit
14kW Tankless Water Heater Electric ORBEK On Demand Heater 240V 3.38GPM
Best forCompact spaces point of use
- Compact size for small areas
- Uses 60% less electricity
ConsiderLower 3.38 GPM flow rate
APUS 18kW Tankless Water Heater Electric, 240V, Up to 4.4 GPM, 3s Instant
Best forSpace-saving installations
- Ultra-slim design saves space
- 99.8% thermal efficiency
ConsiderFlow rate limited to 4.4 GPM
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Pate…
Best forPoint of use small spaces
- 90% smaller than tank heaters
- 99% thermal efficiency
ConsiderLow 13kW power output
Westinghouse 14kW Tankless Water Heater Electric 240V, Wifi, ETL, Gray
Best forSmart home integration
- WiFi and voice control
- 98% thermal efficiency
ConsiderRequires 60A dedicated circuit
Rheem 18kW 240V Tankless Electric Water Heater – Smart Control
Brand: Rheem
A reliable, feature-rich 18kW heater for homeowners who value precise temperature control.
The Rheem 18kW tankless water heater puts precise temperature control at your fingertips with its external digital thermostatic control and LED display, offering +/-1 degree accuracy. This means you can dial in your ideal shower temperature and trust it to stay consistent, even when other fixtures are running. The self-modulating technology adjusts power output to match real-time hot water demand, so you only use energy when you need it, boosting efficiency without sacrificing comfort.
With a flow rate of up to 4.4 GPM, this unit comfortably handles 2-3 simultaneous uses, like a shower and a sink. The durable copper immersion heating elements are field serviceable, extending the heater’s lifespan and simplifying maintenance. Installation is straightforward thanks to the bottom 3/4-inch NPT water connections, making it a practical choice for DIY-minded homeowners who want reliability and control.
- Accurate digital temperature control
- Self-modulating power saves energy
- Field serviceable copper elements
- Requires dedicated 60A breaker
- Flow rate limited to 4.4 GPM
NOVIEEX 18kW Tankless Water Heater – Medium Home Efficiency
Brand: NOVIEEX
An efficient, high-flow 18kW heater ideal for medium-sized homes with multiple hot water needs.
The NOVIEEX 18kW electric tankless water heater is engineered for small-to-medium-sized homes, condos, and apartments, supplying hot water to 2-3 simultaneous points. Its high-capacity flow rate of up to 4.9 GPM easily accommodates multiple running fixtures, so you can enjoy a shower while the dishwasher runs without a noticeable drop in temperature. This makes it a versatile upgrade for typical household routines.
What sets this unit apart is its anti-scald constant temperature technology, maintaining a range from 77°F to 140°F with a crystal-clear LED display. You can precisely set your preferred temperature and trust it to stay stable. Operating at an elite 99.8% thermal efficiency, the NOVIEEX minimizes energy waste, translating to lower utility bills and a smaller carbon footprint—all in a compact, indoor-friendly design.
- High 4.9 GPM flow rate
- Anti-scald constant temperature
- 99.8% thermal efficiency
- Indoor installation only
- Requires 60A dedicated circuit
Rheem RTEX-24 24kW Tankless Water Heater – High Output
Brand: Rheem
A high-output 24kW heater that meets the demands of larger households with ease.
The Rheem RTEX-24 is a powerhouse, delivering up to 5.9 GPM to handle simultaneous showers, laundry, and dishwashing with ease. Its ON/OFF dial control with an adjustable digital temperature display gives you straightforward, reliable temperature management. The self-modulating power control ensures the unit only uses the energy required for your current demand, promoting efficiency without compromising on hot water availability.
This 24kW model is designed for larger households that need a steady, high-volume supply. The bottom 3/4-inch NPT water connections simplify installation, and the robust construction speaks to Rheem’s reputation for durability. If you have the electrical capacity (typically a 100A breaker), this unit offers a seamless upgrade from a tank heater, providing endless hot water for your family’s busiest moments.
- High 5.9 GPM flow rate
- Simple dial temperature control
- Self-modulating for efficiency
- Requires 100A dedicated circuit
- Dial control less precise than digital
NOVIEEX 27kW Tankless Water Heater – Whole House Heavy Duty
Brand: NOVIEEX
A heavy-duty 27kW heater that delivers whole-house hot water with exceptional efficiency.
The NOVIEEX 27kW tankless water heater is a heavy-duty solution built for whole-house demands, seamlessly supplying hot water to 3-4 water points simultaneously. Its industry-topping flow rate of up to 7.4 GPM ensures you can run multiple showers, appliances, and sinks without a drop in performance. This makes it an excellent choice for larger families or homes with high hot water usage.
Featuring a smart master temperature lock, this unit reaches a wide spectrum from 77°F to 140°F with meticulous control, preventing accidental adjustments. The elite eco modulation harnesses a supreme 99.8% energy conversion efficiency, meaning it only heats water when needed, drastically reducing standby losses. For a whole-house system that combines power and intelligence, the NOVIEEX 27kW stands out as a top contender.
- Massive 7.4 GPM flow rate
- Smart temperature lock
- 99.8% energy efficiency
- Requires 125A dedicated circuit
- Larger footprint than smaller models
APUS 27kW Electric Tankless Water Heater – Smart Memory
Brand: APUS
A smart, high-capacity 27kW heater with convenient memory settings for busy households.
The APUS 27kW electric tankless water heater is built for busy homes, delivering up to 6.5 GPM for 3-4 simultaneous uses. Whether it’s back-to-back showers or running the washing machine, this unit keeps up with high demand. Its digital control allows you to adjust the temperature from 86°F to 140°F in 1°F increments, and the built-in memory function automatically recalls your preferred settings, so you never have to fiddle with the dial again.
Self-modulating heating technology matches power output to real-time flow and temperature demand, eliminating standby tank loss and saving energy. The compact wall-mounted design saves valuable floor space, and multiple safeguards—including anti-leakage and overheat protection—ensure safe operation. If you want a powerful, user-friendly heater that remembers your preferences, the APUS 27kW is a compelling option.
- Memory function recalls settings
- 1°F temperature adjustment
- Compact wall-mounted design
- Requires 125A dedicated circuit
- Flow rate slightly lower than NOVIEEX 27kW
ORBEK 14kW Tankless Water Heater – Compact Efficiency
Brand: Orbek
A compact, efficient 14kW heater ideal for small spaces and point-of-use installations.
The ORBEK 14kW tankless water heater is a compact solution for smaller spaces, providing a max flow of 3.38 GPM for 2-3 points of use. It’s perfect for apartments, garages, or cabins where space is at a premium. The unit delivers endless hot water in just 3 seconds, and its high efficiency uses up to 60% less electricity than traditional tank heaters, making it a cost-effective upgrade.
ETL certified, the ORBEK prioritizes safety with advanced protection features, giving you peace of mind. It requires a 240V/60AMP dedicated circuit, so ensure your electrical panel can handle it. For a budget-friendly, reliable option that doesn’t skimp on performance, the ORBEK 14kW is a solid choice for point-of-use or small home applications.
- Compact size for small areas
- Uses 60% less electricity
- ETL certified safety
- Lower 3.38 GPM flow rate
- Requires 60A dedicated circuit
APUS 18kW Tankless Water Heater – Slim Space Saver
Brand: APUS
A slim, efficient 18kW heater that maximizes space without sacrificing hot water performance.
The APUS 18kW tankless water heater delivers instant hot water on demand, supplying up to 4.4 GPM for 2-3 simultaneous uses. Its ultra-slim design—measuring just 13.7 x 11.42 x 3.54 inches—saves valuable floor space and is perfect for whole-house or point-of-use installation. You get endless hot water without the bulk of a traditional tank.
With 99.8% thermal efficiency, the self-modulating technology adjusts power to the actual flow rate, heating water only when needed to reduce standby heat loss. The 6-layer safety protection includes anti-leakage, overheat, and surge safeguards, ensuring safe operation. If you need a reliable, space-saving heater that doesn’t compromise on performance, the APUS 18kW is an excellent pick.
- Ultra-slim design saves space
- 99.8% thermal efficiency
- 6-layer safety protection
- Flow rate limited to 4.4 GPM
- Requires 60A dedicated circuit
EcoSmart ECO 11 Electric Tankless Water Heater – Compact Classic
Brand: EcoSmart
A compact, efficient 13kW heater perfect for point-of-use applications and small spaces.
The EcoSmart ECO 11 is a compact 13kW tankless water heater that provides endless on-demand hot water, perfect for point-of-use applications like a single bathroom or a kitchen sink. Its patented self-modulating technology continuously monitors water temperature and controls flow rates to ensure efficiency and comfort. You get consistent hot water that never runs out, without the energy waste of a tank.
This unit is 90% smaller than traditional tank heaters, and its dimensions of 11.5 x 8 x 3.75 inches make it easy to install on a wall or at the point of use. With 99% thermal energy efficiency, it only heats water when called, unlike a tank that maintains temperature constantly. The EcoSmart ECO 11 is an ideal, budget-friendly choice for supplemental or small-space hot water needs.
- 90% smaller than tank heaters
- 99% thermal efficiency
- Patented self-modulating technology
- Low 13kW power output
- Requires 60A dedicated circuit
Westinghouse 14kW Tankless Water Heater – Smart WiFi Control
Brand: Westinghouse
A smart, efficient 14kW heater with WiFi control for tech-savvy homeowners.
The Westinghouse 14kW tankless water heater brings modern convenience with smart WiFi and voice control, compatible with Alexa and Google Home. You can adjust temperature and monitor usage from your smartphone, making it easy to manage your hot water from anywhere. It delivers hot water in just 3 seconds with 98% thermal efficiency, ensuring quick, cost-effective performance.
ETL certified, this unit requires a dedicated 60A double-pole breaker and 6 AWG wire at 240V for safe, stable operation. The minimum start-up flow is low, so it works well even for low-flow fixtures. If you want a smart, connected heater that offers both efficiency and remote control, the Westinghouse 14kW is a standout choice.
- WiFi and voice control
- 98% thermal efficiency
- ETL certified safety
- Requires 60A dedicated circuit
- Lower 14kW power output
Buyer’s Guide: What to Consider
Choosing the right electric tankless water heater involves balancing your hot water needs with your home’s electrical capacity. Consider these key factors to make an informed decision that ensures endless hot water and energy savings.
- Flow Rate (GPM): Measure your household's peak hot water demand. A typical shower uses 2-3 GPM, a faucet about 1 GPM. Add up simultaneous uses to determine the minimum GPM you need. For 2-3 fixtures, 4-5 GPM works; for 3-4 fixtures, look for 6+ GPM.
- Power Requirements: Electric tankless heaters require dedicated circuits. 14kW units typically need 60A breakers, 18kW need 60-80A, 24kW need 100A, and 27kW need 125A. Check your electrical panel's capacity before purchasing; upgrades can be costly.
- Temperature Control: Look for precise temperature adjustments, ideally in 1°F increments, and digital displays. Some models offer memory functions or smart WiFi control for convenience. Consistent temperature maintenance is crucial for comfort, especially with multiple fixtures running.
- Energy Efficiency: All tankless heaters are more efficient than tank models, but efficiency ratings vary. Look for 99%+ thermal efficiency and self-modulating technology that adjusts power to demand. This reduces energy waste and lowers your utility bills over time.
- Installation and Space: Consider the unit's dimensions and installation requirements. Wall-mounted models save floor space. Ensure you have proper ventilation (most are indoor-rated) and access to water connections. Some models have bottom connections for easier installation.
Conclusion
Electric tankless water heaters offer a space-saving, energy-efficient way to enjoy endless hot water. From compact point-of-use models like the EcoSmart ECO 11 to whole-house powerhouses like the NOVIEEX 27kW, there’s a unit for every home and budget. Prioritize flow rate, power requirements, and smart features to find your perfect match.
For most households, the Rheem 18kW provides reliable performance and precise control, while the APUS 27kW excels for larger families with its memory settings. Assess your needs, check your electrical panel, and invest in a model that will deliver comfort and savings for years to come.
Erica Steven is the founder and lead writer of WorstBrands, a site dedicated to providing honest and trustworthy reviews about outdoor gear and fashion products.
With a passion for exploring the great outdoors and staying up to date on the latest fashion trends, Erica uses her expertise to provide valuable insights into the products that matter most to her readers.
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