Tankless water heaters, also known as demand-type or instantaneous water heaters, provide hot water only as it is needed. They don’t produce the standby energy losses associated with storage water heaters, which can save money. Tankless water heaters heat water instantaneously without the use of a storage tank. When a hot water faucet is turned on, cold water flows through a heat exchanger in the unit, and an electric element heats the water. As a result, tankless water heaters deliver a constant supply of hot water.
- 1 Benefits of Tankless Electric Water Heaters
- 2 Top 10 Tankless Electric Water Heaters for 2025
- 3 Comparison Table of Top Tankless Electric Water Heaters
- 4 Pros and Cons of Tankless Electric Water Heaters
- 5 Test Data and Performance Scenarios
- 6 Buying Guide for Tankless Electric Water Heaters
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7
Frequently Asked Questions (FAQ)
- 7.1 1. How long do tankless electric water heaters last?
- 7.2 2. Can a tankless electric water heater support a large family?
- 7.3 3. Do tankless electric water heaters work during power outages?
- 7.4 4. Are tankless electric water heaters worth the investment?
- 7.5 5. How often should I maintain my tankless electrickahwater heater?
- 8 Conclusion
Benefits of Tankless Electric Water Heaters
Electric tankless water heaters offer numerous benefits compared to traditional tank-style water heaters. These energy-efficient systems only heat water when it is needed, which helps to reduce standby heat loss and minimize energy consumption. As a result, homeowners can enjoy significant savings on their energy bills. One of the key advantages of electric tankless water heaters is their ability to provide unlimited hot water. Unlike tank-style heaters that rely on a limited storage capacity, electric tankless models heat water on demand, ensuring a continuous supply of hot water whenever it is needed. In addition to their energy efficiency and endless hot water, electric tankless water heaters are also compact in size. Their compact design makes them ideal for homes with limited space, allowing for flexible installation in closets, under sinks, or other tight areas.
Energy Efficiency
Electric tankless water heaters are typically around 98 percent or more efficient while gas tankless water heaters are around 80-85 percent efficient. “Choosing between the two often depends on your home’s size and existing utilities,” says Robinson. “Electric tankless heaters are cheaper upfront and easier to install, but they’re better suited for smaller homes or as point-of-use systems.”
Space-Saving Design
A big advantage of all tankless water heaters is their space-saving design ¡ª at roughly the size of a large suitcase, they can be tucked into a closet or mounted high on a wall. The average tankless unit is around 27 inches tall, 18 inches wide, 10 inches deep, and rectangular. Tank-style heaters take up floor space, usually in the basement, while tankless units are mounted to a wall like a circuit breaker and can fit in most closets.
Top 10 Tankless Electric Water Heaters for 2025
Below is a curated list of the top 10 tankless electric water heaters for 2025, based on performance, efficiency, and user feedback. Each model has been evaluated for its flow rate, energy efficiency, and suitability for various household sizes.
1. Stiebel Eltron Tempra 36 Plus
The Stiebel Eltron Tempra 36 Plus is among the most powerful electric tankless water heaters on the market, providing a maximum of 7.5 GPM, which should provide enough hot water for four showers running simultaneously. It can heat water to 140 degrees Fahrenheit, well above the U.S. Department of Energy’s (DOE) maximum recommendation for household water temperature of 110 degrees Fahrenheit. This model also is highly efficient. Given that no system is 100 percent perfect, a rating of 99 percent efficiency places the Stiebel Eltron among the best available.
- Pros: Has an advanced flow control that maintains consistent temperature, no venting required, seven-year leak warranty.
- Cons: Requires 300 amps, potentially needing an electrical service panel upgrade.
2. EcoSmart ECO 27
The EcoSmart ECO 27 electric tankless water heater is a compact unit that still offers competitive performance with a maximum of 6.6 GPM. It also has a minimal activation requirement of 0.3 GPM, so users don’t have to turn faucets on full power to get hot water. A less responsive electric water heater would waste water and electricity used for heating, but this one provides optimal control. Like many other leading devices, this model uses flow modulation when heating water.
- Pros: Lifetime limited warranty, 94% energy efficiency, compact design.
- Cons: Some users reported issues with warranty validation, output drops to 2.7 GPM with cold inlet water.
3. Rheem RTEX-18
The Rheem 18kW 240V Tankless Electric Water Heater stands out for its efficiency and user-friendly design. Users gain precise control over water temperatures with features like a digital temperature display and external thermostatic control. The model’s self-modulation system adjusts power to meet hot water demand, ensuring you use only the energy needed, making it eco-friendly and cost-effective.
- Pros: Durable copper immersion heating elements, field-serviceable, up to 4.4 GPM.
- Cons: High upfront cost compared to traditional models.
4. Eemax Home Advantage II
The thermostatic control can respond to fluctuating temperatures while maintaining a constant hot water supply. The Eemax Home Advantage II has a maximum flow rate of 8.7 GPM at 77¡ãF.
- Pros: High flow rate, self-modulating technology, advanced flow control.
- Cons: Only a one-year limited warranty.
5. Titan SCR4 N-270
Titan is a US-based manufacturer of some of the most prolific electric tankless water heaters on the market. The Titan SCR4 N-270 is currently their most powerful model. The N-270 weighs 12 pounds and is 11.5 x 10.5 x 3 inches, so it does not need much space.
- Pros: 8 GPM maximum flow rate, compact size, 10-year warranty on water components.
- Cons: Limited suitability for colder climates.
6. Thermomate 18kW
The budget-friendly 18 kW Thermomate tankless water heater is an economical solution designed to provide virtually instant hot water for up to three different applications. Despite the low cost, there’s still a digital thermostat adjustable in single-degree increments and self-modulated control for stable temperature output, plus maximum energy savings.
- Pros: Affordable, overheating protection, ETL certified.
- Cons: Requires two 40A breakers, lower flow rate for larger homes.
7. Airthereal 27kW
MOST VERSATILE: Airthereal 27kW Electric Tankless Water Heater. This model offers competitive performance with a maximum of 6.6 GPM, suitable for various household sizes.
- Pros: Versatile for multiple applications, compact design.
- Cons: Requires three 40A breakers.
8. Rheem RTEX-13
BEST FOR CONDOS: Rheem RTEX-13 Professional Classic Water Heater. This model is ideal for smaller households or condos with a flow rate of up to 5 GPM.
- Pros: Easy setup, affordable price.
- Cons: Limited range for larger households.
9. EcoTouch Point-Of-Use
BEST POINT-OF-USE: EcoTouch Point-Of-Use Tankless Water Heater. This model connects to a water line, plugs into a wall outlet, mounts under a sink to give you four gallons of instant hot water when you’re washing your hands.
- Pros: Easy setup, affordable, instant hot water.
- Cons: Prone to leaking, no digital temperature display.
Comparison Table of Top Tankless Electric Water Heaters
| Model | Max Flow Rate (GPM) | Power (kW) | Efficiency (%) | Warranty | Price Range |
|---|---|---|---|---|---|
| Stiebel Eltron Tempra 36 Plus | 7.5 | 36 | 99 | 7-year leak, 3-year parts | $800-$900 |
| EcoSmart ECO 27 | 6.6 | 27 | 94 | Lifetime limited | $400-$500 |
| Rheem RTEX-18 | 4.4 | 18 | 98 | Not specified | $300-$400 |
| Eemax Home Advantage II | 8.7 | Not specified | Not specified | 1-year limited | $600-$700 |
| Titan SCR4 N-270 | 8.0 | 11 | Not specified | 10-year water components | $200-$300 |
| Thermomate 18kW | Not specified | 18 | Not specified | Not specified | $200-$300 |
| Airthereal 27kW | 6.6 | 27 | Not specified | Not specified | $400-$500 |
| Rheem RTEX-13 | 5.0 | 13 | Not specified | Not specified | $200-$300 |
| EcoTouch Point-Of-Use | 4.0 | Not specified | Not specified | 6-year tank, 2-year parts | $100-$200 |
| iHeat S-16 | Not specified | 16 | Not specified | Limited | $200-$300 |
Pros and Cons of Tankless Electric Water Heaters
Pros
- Energy efficient: Can reduce electricity costs by up to 50%.
- Unlimited hot water: Provides continuous hot water on demand.
- Space-saving design: Compact and wall-mounted, ideal for small spaces.
- Long lifespan: Most units last over 20 years with proper maintenance.
Cons
- Higher upfront cost: Ranges from $500-$1,500, plus installation costs of $1,150-$4,500.
- Potential electrical upgrades: May require a 300-amp service or multiple breakers.
- Flow rate limitations: May struggle with simultaneous high-demand usage in large households.
- Installation complexity: Requires professional installation, especially for electrical wiring.
Test Data and Performance Scenarios
Consumer Reports recently tested several electric whole-house tankless water heaters from brands such as Bosch, Rheem, and Stiebel Eltron. Following a “heavy use” industry standard test, they compared the performance of electric tankless water heaters with conventional tanked heaters. The test used a high draw pattern equal to using 84 gallons of water per day. Because the tankless water heaters performed so similarly to each other, they averaged the results and compared that score with the performance of conventional storage tanks. The annual operating cost for an electric tankless model was $535, compared to $580 for a conventional electric tank.
In a real-world scenario, a family of four might take several showers, run the dishwasher, and wash laundry in a day, totaling 100 gallons of hot water. A typical shower uses up to 2.5 GPM, and a dishwasher might use 1-2 GPM. The Stiebel Eltron Tempra 36 Plus, with its 7.5 GPM capacity, can handle four showers simultaneously, while the Rheem RTEX-13, with 5 GPM, is better suited for smaller households with one or two simultaneous uses.
Buying Guide for Tankless Electric Water Heaters
Key Considerations
- Flow Rate (GPM): A 1- or 2-bath home typically needs around 5 GPM, while a 3- or 4-bath home needs a 10 GPM unit. Water supply temperature impacts GPM, meaning a model fitted in the southern U.S. would provide a higher GPM than one fitted in northern states.
- Electrical Capacity: A whole house electric tankless water heater can use more than 25,000 watts of electricity, compared to 5,000 watts for a conventional water heater. Ensure your home’s electrical panel can handle the load.
- Installation Requirements: Electric models don’t require venting, but they may need significant electrical upgrades. Professional installation is recommended.
- Climate: In colder climates, the incoming water temperature is lower, reducing the GPM output. For example, the EcoSmart ECO 27 drops to 2.7 GPM with cold inlet water.
Steps to Choose the Right Model
- Assess your household’s hot water needs based on the number of fixtures and peak usage times.
- Check your electrical panel’s capacity and consult an electrician if upgrades are needed.
- Compare flow rates and efficiency ratings to match your climate and household size.
- Review warranty terms and customer feedback for reliability and service.
- Get quotes from licensed plumbers for installation costs.
Frequently Asked Questions (FAQ)
1. How long do tankless electric water heaters last?
Most tankless electric water heaters have a lifespan of over 20 years with proper maintenance, compared to 10-15 years for traditional tank heaters.
2. Can a tankless electric water heater support a large family?
Yes, but you’ll need a high-capacity model like the Stiebel Eltron Tempra 36 Plus with a flow rate of 7.5 GPM or higher to handle multiple simultaneous uses.
3. Do tankless electric water heaters work during power outages?
No, they require electricity to operate, unlike tank-style heaters that can retain hot water for days without power.
4. Are tankless electric water heaters worth the investment?
For smaller households or those in warm climates, they offer significant energy savings and space efficiency, but the high upfront cost and potential electrical upgrades may delay the payback period for larger homes.
5. How often should I maintain my tankless electrickahwater heater?
Annual maintenance by a professional is recommended, or twice yearly in areas with hard water or cold climates, to prevent scale buildup and ensure efficiency.
Conclusion
Tankless electric water heaters are a smart choice for homeowners seeking energy efficiency, space savings, and endless hot water. Models like the Stiebel Eltron Tempra 36 Plus and EcoSmart ECO 27 stand out for their performance and reliability. By assessing your household’s needs, electrical capacity, and climate, you can select the perfect model to enjoy long-term savings and comfort. For more information on energy-efficient home appliances, visit Energy.gov.