When it comes to upgrading your hot water system, choosing the right tankless water heater can make all the difference. In 2025, there are several efficient and reliable options that not only save on energy costs but also provide a steady supply of hot water. From compact designs to advanced features, these models cater to various household needs. So, which ones stand out as the best choices? Let’s explore the top contenders.
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
If you’re looking for an energy-efficient water heating solution, the Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater is an excellent choice for homeowners. With a compact design measuring just 8.25W x 12.62H inches, it fits seamlessly into your space. This electric model delivers a powerful 13 kW output and heats water up to 140°F while maintaining a remarkable 99.8% energy efficiency. Plus, the external digital control allows you to adjust temperatures with precision. Enjoy a maximum flow rate of 4.8 GPM, ensuring you won’t run out of hot water. Installation is simple, making this water heater user-friendly.
Best For: Homeowners seeking an energy-efficient and compact solution for continuous hot water supply.
Pros:
- 99.8% energy efficiency helps reduce utility bills and environmental impact.
- Compact design allows for easy installation in smaller spaces or wall-mounted applications.
- External digital control enables precise temperature adjustments for optimal comfort.
Cons:
- Limited flow rate of 4.8 GPM may not suffice for larger households with simultaneous hot water needs.
- Electric model requires a dedicated 240V electrical connection, which may necessitate additional installation costs.
- Field serviceable heating elements may require DIY maintenance skills or professional assistance for replacements.
EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 Electric Tankless Water Heater is an excellent choice for homeowners with limited space who need a reliable source of hot water. With its compact dimensions of just 11.5 x 8 x 3.75 inches, it fits easily in tight spots. This unit boasts a powerful 13KW heating capacity and patented self-modulating technology, delivering on-demand hot water without running out. You’ll enjoy consistent temperatures within 1°F of your setting and a maximum flow rate of 3.1 gallons per minute. Plus, the lifetime warranty on electronics offers peace of mind for your investment.
Best For: Homeowners with limited space who require a reliable and efficient hot water solution.
Pros:
- Compact design: At 90% smaller than traditional tank heaters, it fits easily in tight spaces.
- Endless hot water: Provides on-demand hot water, ensuring you never run out.
- High efficiency: Offers 99% thermal energy efficiency and maintains consistent temperatures.
Cons:
- Limited flow rate: Maximum flow rate of 3.1 gallons per minute may not be sufficient for larger households.
- Temperature limitation: Best suited for climates with incoming water temperatures of 67°F and above.
- Amperage requirement: Requires a significant amperage draw (54 A), which may necessitate electrical upgrades in some homes.
Rheem 18kW 240V Tankless Electric Water Heater, Gray
For homeowners seeking an energy-efficient hot water solution, the Rheem 18kW 240V Tankless Electric Water Heater stands out with its impressive 99.8% efficiency rating. This compact, wall-mounted heater delivers a flow rate of up to 4.4 GPM, ensuring you have hot water when you need it. Its self-modulation technology adjusts power based on demand, potentially cutting your heating bills by 50%. With an external digital thermostatic control and a sleek gray design, it’s easy to use and install. Plus, its durable copper heating elements promise longevity, making it a smart investment for your home.
Best For: Homeowners looking for an energy-efficient, space-saving hot water solution that offers consistent performance and easy installation.
Pros:
- High efficiency rating of 99.8%, significantly reducing heating costs.
- Compact design saves space, allowing versatile installation options.
- Self-modulation technology adjusts heating based on demand, ensuring hot water availability.
Cons:
- Requires proper electrical setup, which may necessitate professional installation.
- Limited to a maximum temperature of 140°F, which may not meet all users’ preferences.
- Initial investment may be higher compared to traditional tank water heaters.
ThermoMate Natural Gas Tankless Water Heater (CZ422NG)
Looking for an efficient water heating solution for your entire home? The ThermoMate Natural Gas Tankless Water Heater (CZ422NG) delivers a powerful 102,000 BTU, providing unlimited hot water on demand. With a remarkable flow rate of 4.7 GPM, you can use 3-4 fixtures simultaneously without any waiting time. Its advanced sensor optimizes heating 20,000 times per second, achieving a thermal efficiency of 98%. Plus, built-in safety features guarantee peace of mind. The user-friendly 3.5-inch LED touchscreen makes adjustments easy, while its compact design saves space. Enjoy the benefits of reduced operating costs and reliable performance in any weather.
Best For: Homeowners looking for an efficient, space-saving water heater that provides unlimited hot water on demand for multiple fixtures.
Pros:
- Delivers unlimited hot water with a flow rate of 4.7 GPM for 3-4 fixtures simultaneously.
- High thermal efficiency of 98% reduces annual operating costs by approximately 30% compared to traditional systems.
- Compact design and user-friendly LED touchscreen make installation and operation easy.
Cons:
- Requires natural gas connection, limiting use in areas without gas supply.
- Initial installation costs may be higher compared to traditional tank water heaters.
- Performance may vary based on the water pressure and temperature of the incoming water supply.
Rinnai V75IN Tankless Hot Water Heater
Experience endless hot water with the Rinnai V75IN Tankless Hot Water Heater, perfect for busy households that juggle multiple appliances. With a high-performance flow rate of 7.5 GPM, you can run up to five fixtures simultaneously without a hitch. This natural gas unit offers energy-efficient operation, heating water only when needed. Its compact design fits well in various spaces, and enhanced scale detection helps prevent long-term damage. Enjoy peace of mind with a 10-year warranty on the heat exchanger and a leak detection feature to protect your home. Consider professional installation for ideal performance and reliability.
Best For: Busy households that require a reliable and energy-efficient hot water solution for multiple appliances running simultaneously.
Pros:
- High-performance flow rate of 7.5 GPM allows for simultaneous use of up to five fixtures.
- Energy-efficient operation only heats water as needed, reducing energy costs.
- Compact design fits into various spaces, making it suitable for different household sizes.
Cons:
- Requires professional installation, which may incur additional costs.
- Wi-Fi monitoring requires an additional Controlr module, not included with the purchase.
- Limited warranty on parts (1 year) compared to some competitors.
Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
The Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater is an excellent choice for homeowners seeking reliable, on-demand hot water without the bulk of traditional tanks. With a powerful 27,000 watts and advanced self-modulation, it adjusts to your hot water needs efficiently. The external digital thermostatic control features a clear LED display for precise temperature management. Weighing just 17.8 pounds, it’s easy to install with bottom 3/4 inch NPT connections. Plus, its durable copper heating elements are serviceable, ensuring longevity. Enjoy continuous hot water for multiple applications while enjoying high efficiency and outstanding performance.
Best For: Homeowners looking for an efficient and space-saving solution for continuous hot water supply.
Pros:
- High efficiency with advanced self-modulation that adjusts to hot water demand.
- Easy installation with bottom 3/4 inch NPT connections and lightweight design.
- Durable construction featuring serviceable copper heating elements for longevity.
Cons:
- Limited flow rate of 0.11 gallons per minute may not suffice for simultaneous uses.
- Requires electrical setup which may necessitate professional installation in some homes.
- Average customer rating of 4.2 out of 5 stars suggests mixed feedback on performance.
EcoSmart ECO 27 Tankless Water Heater
If you’re in a cold climate or have high water demands, the EcoSmart ECO 27 Tankless Water Heater is an excellent choice. This electric unit, with a powerful 27-kW output, delivers a maximum flow rate of 6.6 gallons per minute. It’s designed with self-modulating technology, meaning it efficiently adjusts energy usage based on your water flow. The digital display allows for precise temperature control in 1-degree increments. Weighing just 11 lbs and measuring 17 x 17 x 3.5 inches, it’s easy to mount on your wall. Plus, it features a limited lifetime warranty on key components for added peace of mind.
Best For: Individuals in cold climates or households with high water demands looking for an efficient and space-saving water heating solution.
Pros:
- Energy Efficient: Achieves an impressive 99.8% energy efficiency, reducing energy costs.
- High Flow Rate: Capable of delivering up to 6.6 gallons per minute, suitable for large tubs and multiple fixtures.
- Compact Design: Lightweight and wall-mounted, saving valuable space in your home.
Cons:
- Requires Significant Electrical Setup: Needs three 40 DP breakers and 8 AWG wiring, which may necessitate professional installation.
- Limited Maximum Temperature: Maximum output temperature is capped at 120°F, which may not meet all users’ preferences.
- Warranty Limitations: The limited lifetime warranty does not cover labor or incidental damages, which could lead to additional costs.
Titan Electric Tankless Water Heater
For homeowners seeking an efficient and space-saving solution for hot water needs, the Titan Electric Tankless Water Heater stands out as a top choice in 2025. This model, the N-120, operates at 220 volts with a powerful 11,800 watts and boasts an impressive efficiency rating of 99.5%. Weighing just 7.54 pounds and measuring 9.6 inches wide, it’s easy to install on your wall. With dual heating chambers and on-demand control, you’ll enjoy instant hot water without the wait. Plus, it comes with long warranties, ensuring reliability. Rated 4.5 stars by customers, it’s a smart investment for your home.
Best For: Homeowners looking for an energy-efficient, space-saving solution for their hot water needs.
Pros:
- High energy efficiency rating of 99.5%, reducing energy costs.
- Compact design allows for easy wall-mounted installation in limited spaces.
- On-demand water control provides instant hot water without waiting.
Cons:
- Requires a 220V electrical connection, which may necessitate professional installation.
- Limited to indoor use, restricting placement options.
- The initial purchase price may be higher compared to traditional water heaters.
ORBEK 14kW Electric Tankless Water Heater
Looking for a compact and highly efficient solution for your hot water needs? The ORBEK 14kW Electric Tankless Water Heater delivers on-demand hot water in just 3 seconds, with a flow rate of up to 3.38 GPM for 2-3 points of use. Its sleek dimensions save over 50% space compared to traditional tanks, while its high energy efficiency can cut electricity costs by up to 60%. With advanced safety features and a user-friendly LED display, you’ll enjoy stable temperature control and peace of mind. Plus, you can count on 24/7 customer support for any questions or concerns.
Best For: Homeowners looking for a compact, energy-efficient solution for instant hot water availability in multiple locations.
Pros:
- High energy efficiency can reduce electricity costs by up to 60%.
- Provides endless hot water in just 3 seconds, suitable for multiple points of use.
- Advanced safety features including leakage and over-temperature protection ensure peace of mind.
Cons:
- Requires professional installation due to specific electrical and plumbing requirements.
- Limited flow rate may not support larger households with high simultaneous hot water demands.
- Initial cost may be higher compared to traditional tank water heaters.
EcoSmart ECO 18 Electric Tankless Water Heater
The EcoSmart ECO 18 Electric Tankless Water Heater is an excellent choice for homeowners seeking energy efficiency and reliable hot water on demand. With an impressive 18 kW power output and a 99.8% efficiency rating, it provides a maximum flow rate of 3.51 gallons per minute. Its compact, wall-mounted design makes it easy to fit into tight spaces. Plus, the digital temperature control allows you to adjust the heat in one-degree increments. Ideal for warmer climates, it supports multiple showers simultaneously. Backed by a lifetime warranty on key components, this unit guarantees long-lasting performance and peace of mind.
Best For: Homeowners in warmer climates seeking an energy-efficient solution for on-demand hot water.
Pros:
- High Efficiency: With a 99.8% efficiency rating, it minimizes energy waste.
- Compact Design: The wall-mounted design allows for easy installation in tight spaces.
- Multiple Showers: Capable of supporting multiple showers simultaneously in warm climates.
Cons:
- Temperature Limitations: Best performance is in climates with incoming water temperatures of 62°F and above.
- Limited Flow Rate: May struggle to meet demand in colder climates or larger households.
- Electricity Dependent: Requires a 240-volt electrical supply, limiting installation options.
Factors to Consider When Choosing Residential Tankless Water Heaters
When choosing a residential tankless water heater, you’ll want to contemplate several key factors. Flow rate capabilities, energy efficiency ratings, and installation requirements can greatly impact your decision. Additionally, think about temperature control features and warranty options to guarantee you get the best value for your investment.
Flow Rate Capabilities
Choosing the right flow rate for your tankless water heater is essential for meeting your household’s hot water demands. Flow rate, measured in gallons per minute (GPM), indicates how much hot water your unit can deliver at once. You’ll want to take into account the maximum flow rate required by your fixtures—like showers, sinks, and appliances—especially during peak usage times. High-demand households may need units with flow rates of 7 GPM or more to guarantee simultaneous use, while smaller homes often do well with 3-4 GPM models. Remember, ambient water temperature can impact flow rate; colder incoming water may reduce the hot water your unit can provide. Selecting the right flow rate will help prevent inconsistent water temperature during busy times.
Energy Efficiency Ratings
Understanding energy efficiency ratings is vital for selecting the right residential tankless water heater, as these ratings directly impact your energy bills and environmental footprint. Look for units with thermal efficiency ratings of 98% to 99%, meaning they convert nearly all the energy used into hot water. The Energy Factor (EF) is another important metric; a higher EF indicates you’ll get more hot water per unit of energy consumed. Additionally, consider models with self-modulating technology, which adjusts energy usage based on demand, ensuring you’re only using power when hot water’s needed. By choosing a tankless water heater with a high energy efficiency rating, you can greatly lower your water heating bills and reduce your environmental impact compared to traditional tank models.
Installation Requirements
Selecting a tankless water heater isn’t just about energy efficiency; installation requirements play a significant role in ensuring you get the most out of your investment. Most units need a dedicated electrical circuit, often with a two-pole breaker to accommodate their high wattage and amperage. You’ll also need proper wiring sizes, like 6 AWG for higher wattage models, to guarantee safety and efficiency. Most heaters come with standard pipe fittings, like 1/2 NPT, making them compatible with your existing plumbing. Additionally, wall mounting is a popular option, allowing for flexible placement throughout your home. If you’re opting for a gas model, remember that proper venting is essential, with specific dimensions and materials required for safe operation and compliance with local codes.
Temperature Control Features
When it comes to residential tankless water heaters, temperature control features are essential for optimizing both comfort and efficiency. You’ll want to look for external digital thermostatic controls that allow you to adjust the temperature with +/- 1-degree accuracy. Many models use patented self-modulating technology, which maintains a consistent output temperature, minimizing energy consumption by heating water only when needed. Advanced systems can adjust heating power up to 20,000 times per second, ensuring a reliable supply during demand fluctuations. LED displays make it easy to monitor water flow and heating status, while maximum temperature settings can reach up to 140°F, catering to various household needs and incorporating safety features to prevent overheating.
Warranty and Support Options
While choosing a residential tankless water heater, warranty and support options play an essential role in ensuring long-term satisfaction. Start by reviewing the warranty duration; many models offer lifetime warranties on key components like electronics and heat exchangers, though labor costs might not be included. Check if the manufacturer provides 24/7 customer service and straightforward access to warranty claims or technical assistance. A favorable return policy, often a 30-day guarantee, is important if the unit doesn’t meet your expectations. Look for readily available warranty documentation to understand coverage details before you buy. Finally, access to user manuals or troubleshooting guides can greatly enhance your experience with the product.
