If you’re considering upgrading your home’s hot water system, tankless water heaters are a smart choice for efficiency and reliability. With numerous options available in 2025, it’s crucial to know which models stand out for their performance and energy savings. From smart technology to compact designs, these heaters cater to various needs. But how do you decide which one is right for your home? Let’s explore the top contenders that promise endless hot water without breaking the bank.
NEW Rinnai RXP199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU
The NEW Rinnai RXP199iN Condensing Smart Sense Tankless Water Heater is perfect for homeowners seeking efficiency and convenience. This compact unit runs on natural gas or propane and offers an impressive capacity of up to 11.1 GPM, supporting multiple fixtures simultaneously. With a high energy efficiency rating of .98, you’ll save on utility bills while enjoying hot water on demand. The integrated Smart-Circ technology learns your water usage patterns, optimizing performance. Plus, you can manage it remotely with WiFi control. For best results, consider professional installation, and utilize the Rinnai Central App for setup and support. Enjoy endless hot water!
Best For: Homeowners seeking an efficient and compact tankless water heater that provides endless hot water for multiple fixtures.
Pros:
- High capacity: Supports up to 11.1 GPM, allowing multiple fixtures to be used simultaneously.
- Energy efficient: Super-high UEF of .98 helps reduce utility bills.
- Smart technology: Features Smart-Circ Intelligent Recirculation for optimized water usage and WiFi control for remote management.
Cons:
- Professional installation recommended: May require hiring a technician for optimal setup.
- Outdoor installation requires additional components: Needs RX-OVC vent cap for outdoor use.
- Control module not included: WiFi control requires a separate Controlr module purchase.
VEVOR Electric Tankless Water Heater, 13.8KW Instant Hot Water Heater, Digital Temperature Display & Easy Installation & 24-Hour Water Supply, For Kitchen Bathroom Shower Mall Salon
Looking for a reliable hot water solution that fits perfectly in tight spaces? The VEVOR Electric Tankless Water Heater is your answer. With a compact design, this 13.8KW unit delivers instant hot water, reaching temperatures up to 140°F without preheating. The digital temperature display allows you to set precise levels, ensuring comfort in your kitchen, bathroom, or salon. It’s easy to install, but professional help is recommended for peak performance. While it’s well-rated for quick heating, some users suggest opting for a higher wattage model for larger demands. Enjoy a 30-day return policy and VEVOR’s support for peace of mind.
Best For: Those seeking an efficient and space-saving hot water solution for kitchens, bathrooms, or salons.
Pros:
- Instant hot water delivery without the need for preheating.
- Compact wall-mount design saves valuable space.
- Digital temperature display allows for precise temperature control.
Cons:
- Some users report limited hot water supply for larger applications, such as showers.
- Installation complexity may require professional assistance.
- Mixed reviews on customer support responsiveness and effectiveness.
ThermoMate Electric Tankless Water Heater, 11kW 208~240 Volt, On Demand Instant Hot Water Heater, Self Modulating Energy Saving, Save Space, 2.15GPM at 35°F Rise
For those seeking an efficient and space-saving solution for instant hot water, the ThermoMate Electric Tankless Water Heater stands out with its impressive self-modulating technology. With an 11kW power output and a flow rate of 2.15 GPM at a 35°F rise, you’ll enjoy continuous hot water without the bulk of a traditional tank. Its 99% efficiency can save you up to 60% on energy costs. Weighing only 14.3 pounds, it easily mounts on the wall, making it perfect for small spaces. Plus, safety features like overheating protection guarantee a reliable and worry-free experience.
Best For: Individuals or families looking for an energy-efficient, space-saving solution for instant hot water in small homes or low-flow applications.
Pros:
- 99% efficiency leads to significant energy cost savings, up to 60% compared to traditional tank heaters.
- Endless hot water supply with precise temperature control within 1°F.
- Compact, wall-mounted design that saves space and is easy to install.
Cons:
- Flow rate may be limited under certain conditions, potentially affecting simultaneous hot water use.
- Requires a specific electrical setup, including a 60Amp breaker, which may necessitate professional installation.
- Not suitable for larger homes with high hot water demands in multiple locations at the same time.
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
With its patented self-modulating technology, the EcoSmart ECO 11 Electric Tankless Water Heater is perfect for homeowners seeking energy efficiency and reliable hot water on demand. Operating at 13KW and 240 Volts, this unit offers endless hot water, maintaining a consistent temperature within 1 degree of your setting. It boasts an impressive 99.8% thermal efficiency, heating water only when needed. Compact and versatile, it’s 90% smaller than traditional models, allowing for flexible installation. With a flow rate of up to 3.1 GPM, it’s suitable for various applications, making it a top choice among water heaters.
Best For: Homeowners seeking an energy-efficient, compact solution for on-demand hot water.
Pros:
- 99.8% thermal energy efficiency ensures minimal energy waste by heating water only when needed.
- Compact design is 90% smaller than traditional tank heaters, allowing for versatile installation options.
- High customer satisfaction with a rating of 4.3 out of 5 stars from over 5,600 reviews.
Cons:
- May not be sufficient for simultaneous use in larger households, especially in colder climates.
- Requires a specific electrical setup (240 Volts) which may necessitate professional installation.
- Initial cost may be higher compared to traditional tank water heaters.
Rheem 18kW 240V Tankless Electric Water Heater, Gray
The Rheem 18kW 240V Tankless Electric Water Heater is an excellent choice for homeowners seeking an efficient and space-saving solution for their hot water needs. With a maximum flow rate of 4.4 GPM and an impressive 99.8% efficiency, you’ll enjoy continuous hot water while saving on utility bills. Its compact design, measuring just 14.5W x 18.25H inches, allows for flexible wall mounting. The external digital thermostatic control guarantees precise temperature regulation, while the durable copper heating elements are field-serviceable. Plus, with a solid customer rating of 4.3 stars, this unit is a reliable option for your home.
Best For: Homeowners looking for an efficient, space-saving hot water solution with a continuous supply.
Pros:
- High efficiency: At 99.8%, it significantly reduces water heating bills.
- Compact design: Takes up less space compared to traditional tank heaters, allowing for flexible installation.
- User-friendly controls: Features an external digital thermostatic control for precise temperature adjustments.
Cons:
- Initial cost: Higher upfront investment compared to traditional water heaters.
- Requires adequate electrical supply: Must have a compatible electrical system for installation.
- Limited flow rate: Maximum flow rate of 4.4 GPM may not suffice for larger households with high hot water demand.
NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU
Rinnai’s RX199iN Condensing Smart Sense Tankless Water Heater is an excellent choice for homeowners seeking efficient hot water solutions without the bulk of traditional tanks. Operating on natural gas or propane, this compact unit provides up to 11.1 GPM, easily supporting multiple fixtures. Its impressive 199,000 BTU output guarantees you’ll never run out of hot water. Designed for both indoor and outdoor installation, the RX199iN boasts an energy efficiency rating of UEF .98. Plus, with features like Wi-Fi connectivity and a Quick Flush maintenance option, you’ll enjoy convenience and longevity that traditional heaters can’t match.
Best For: Homeowners looking for an efficient and space-saving hot water solution that can support multiple fixtures simultaneously.
Pros:
- Energy efficient with a UEF rating of .98, helping to lower utility bills.
- Compact design allows for flexible installation in both indoor and outdoor settings.
- Advanced features like Wi-Fi connectivity and Quick Flush maintenance for enhanced convenience.
Cons:
- Professional installation recommended, which may incur additional costs.
- Control-R module for Wi-Fi connectivity is sold separately, adding to overall expense.
- Limited to natural gas or propane, making it unsuitable for electric-only homes.
110V Tankless Water Heater Electric, 3000W Compact Water Heater Under Sink, Conveniently Convertible Between Fahrenheit and Celsius
For homeowners seeking efficient space-saving solutions, the 110V Tankless Water Heater Electric, with its compact design and 3000W power, is an ideal choice. This under-sink model offers a quick installation process, requiring only a circuit breaker of 32AMP and a 1/2 NPT thread size. You’ll appreciate its dual temperature scale, allowing you to easily switch between Fahrenheit and Celsius for monitoring comfort. Its electric, tankless design not only saves energy but also helps lower your carbon footprint, making it an environmentally friendly option. Enjoy reliable hot water on demand while maximizing your space and minimizing your energy bills.
Best For: Homeowners looking for a compact and energy-efficient hot water solution for under-sink installation.
Pros:
- Compact design saves space and is perfect for smaller homes or apartments.
- Easy installation process with minimal requirements.
- Environmentally friendly and cost-saving due to its tankless electric design.
Cons:
- Limited to 110V, which may not be suitable for larger households with higher hot water demands.
- Requires a specific circuit breaker size, which may necessitate electrical system upgrades.
- May not provide hot water simultaneously for multiple outlets due to its power capacity.
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
Looking for a reliable hot water solution that fits in tight spaces? The Rheem 240V Heating Chamber RTEX-13 is your answer. With a compact design, it boasts a 99.8% energy efficiency and delivers up to 3.17 gallons per minute. You’ll enjoy endless hot water thanks to its self-modulating power control and durable copper heating elements. The external digital thermostatic control makes adjusting temperatures a breeze, ensuring consistent comfort. While installation may require professional help, its user-friendly features and reliable performance make it a top choice for any home. Just remember to clean it annually for peak operation.
Best For: Homeowners seeking a compact and efficient tankless water heater that provides endless hot water on demand.
Pros:
- Endless hot water supply for single or multiple applications.
- 99.8% energy efficiency leads to significant energy savings.
- User-friendly external digital thermostatic control for easy temperature adjustment.
Cons:
- Requires a high electrical current with a 60 amp breaker.
- Some users report longer heating times if maintenance is neglected.
- Installation may necessitate professional assistance, especially in tight spaces.
Rheem 11kW 240V Tankless Electric Water Heater
The Rheem 11kW 240V Tankless Electric Water Heater stands out as an excellent choice for homeowners seeking a space-saving solution for on-demand hot water. With a flow rate of up to 2.68 GPM, this compact unit is 90% smaller than traditional tanks, making it easy to mount under sinks or in tight spaces. Its adjustable digital temperature display and self-modulating power control guarantee energy efficiency, boasting a 99.8% efficiency rating. Weighing just 7.04 pounds, it’s lightweight yet highly effective, making it a reliable option for your hot water needs. Plus, the LED display adds modern convenience.
Best For: Homeowners looking for a space-efficient, energy-efficient solution for on-demand hot water in smaller living spaces.
Pros:
- Compact design allows for flexible installation in tight spaces, such as under sinks.
- High efficiency rating of 99.8% ensures minimal energy waste and lower utility bills.
- Features an adjustable digital temperature display and self-modulating power control for user convenience.
Cons:
- Flow rate of 2.68 GPM may not be sufficient for larger households with high hot water demands.
- Requires a 240V electrical supply, which may necessitate professional installation if not already available.
- Limited warranty information may raise concerns regarding long-term reliability.
Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel
Rheem’s RRTGH84DVLN3701171 model stands out as the ideal choice for homeowners seeking an efficient and reliable indoor natural gas tankless water heater. With a flow rate of 8.4 GPM and a powerful 157,000 BTU, it provides ample hot water for your needs. Its compact design measures just 17.7W x 23.7H x 9.8D inches, making it perfect for smaller spaces. Featuring exclusive Hot Start Programming and an efficiency rating of 0.93, you’ll enjoy consistent performance. Plus, with a 15-year heat exchanger warranty, you can trust its durability. Customers rate it 4.3 out of 5 stars, reflecting its reliability.
Best For: Homeowners looking for an efficient and space-saving indoor natural gas tankless water heater.
Pros:
- High flow rate of 8.4 GPM ensures sufficient hot water for multiple applications simultaneously.
- Compact design allows for installation in small areas, saving valuable floor space.
- 15-year heat exchanger warranty provides peace of mind regarding durability and long-term performance.
Cons:
- Indoor installation only may limit options for homes without suitable venting.
- Requires a natural gas line, which may not be available in all homes.
- Initial installation cost can be higher compared to traditional tank water heaters.
Factors to Consider When Choosing Tankless Water Heaters
When you’re choosing a tankless water heater, consider factors like fuel type and flow rate to match your needs. Energy efficiency ratings and installation compatibility can save you money and hassle in the long run. Don’t forget to account for space requirements to guarantee a proper fit in your home.
Fuel Type Considerations
Choosing the right fuel type for your tankless water heater can considerably impact both efficiency and installation ease. You can opt for electric or gas models. Electric units are often easier to install, but they require significant electrical capacity and dedicated circuits. On the other hand, gas models typically have a higher BTU rating, allowing quicker heating and the ability to support multiple fixtures at once. Consider the availability of fuel in your area as well—gas models need a steady supply of natural gas or propane, while electric units depend on local electricity rates and grid reliability. Evaluating these factors will help you make an informed decision that suits your needs.
Flow Rate Requirements
Understanding flow rate requirements is essential for selecting the right tankless water heater for your home. The flow rate, measured in gallons per minute (GPM), indicates how many fixtures can run simultaneously without depleting hot water. Most residential units range from 2 to 11 GPM, depending on the model and temperature rise. For instance, a flow rate of 2.15 GPM suits small sinks, while larger households may need up to 11.1 GPM to accommodate multiple showers and appliances at once. Remember to factor in the incoming water temperature and your desired output temperature, as greater temperature rises can reduce available GPM. Assess your household’s hot water demands to determine the necessary flow rate for ideal performance.
Energy Efficiency Ratings
While considering a tankless water heater, it’s important to pay attention to energy efficiency ratings, as these can greatly impact your long-term energy costs. Look for the Uniform Energy Factor (UEF), which indicates the overall efficiency; higher UEF values mean better performance. Most modern units achieve over 90% efficiency, with some reaching 99%, converting nearly all energy into hot water. For electric models, higher kilowatt outputs usually provide more hot water on demand and enhance energy efficiency. Gas-powered heaters typically have energy factors between 0.82 and 0.98, with top models using condensing technology to capture extra heat. By choosing an efficient tankless water heater, you could save 20-40% on your water heating bills compared to traditional systems.
Installation Compatibility
When you’re looking to install a tankless water heater, it’s crucial to take into account several compatibility factors to guarantee a smooth integration into your home. First, check the electrical requirements, making sure your system can handle the necessary amperage and circuit breaker specifications. Next, confirm the water inlet and outlet sizes, which typically require standard NPT fittings for seamless plumbing integration. You’ll also want to review installation options—whether indoor or outdoor—and verify adequate venting for gas models. Additionally, confirm the unit’s maximum flow rate and temperature rise can meet your household’s hot water demands. By addressing these factors, you’ll set yourself up for a successful tankless water heater installation.
Space Requirements
After ensuring your tankless water heater is compatible with your home’s systems, the next consideration is the space it will occupy. Tankless water heaters are typically compact, often about the size of a small suitcase, making them ideal for tight spaces. You can opt for wall-mounted models to save floor space and gain flexibility in placement. Many units are up to 90% smaller than traditional tank heaters, allowing for installation under sinks or in closets. Keep in mind the dimensions and weight of the unit, as some may need stronger wall supports or specific clearance. These space-saving designs not only fit neatly into your home but also tend to reduce maintenance needs due to lower corrosion and scale buildup.
Maintenance Needs
To guarantee your tankless water heater operates efficiently and lasts as long as possible, regular maintenance is essential. You should descale your unit every 6-12 months, especially if you have hard water, to prevent mineral buildup that can hinder performance. Look for models with a Quick Flush design, which simplifies access for cleaning. Don’t forget to check the air intake and exhaust vents periodically to maintain proper airflow and combustion efficiency. Some heaters might need filter or anode rod replacements at specified intervals to avoid corrosion. If you opt for a WiFi-capable model, you can monitor its performance and receive alerts about maintenance needs, helping you address issues before they escalate.