10 Best Tankless Water Heaters 2025 in the United States

The Rinnai RXP199iN Condensing Smart Sense Tankless Water Heater offers impressive versatility, operating with either natural gas or propane and being suitable for both indoor and outdoor installations. With a flow rate of up to 11.1 GPM, it can handle multiple fixtures at once, making it ideal for larger households. Its compact size and modern design, which includes features like Quick Flush and Smart-Circ Intelligent Recirculation, enhance its efficiency and user-friendliness.

Additionally, the unit boasts a high energy efficiency factor of 0.98, translating to significant energy savings. The option for WiFi connectivity through the Control-R module adds to its smart appeal, although this module is not included with the water heater. Installation should be performed by a professional, which adds to the initial cost but ensures proper setup and operation. The unit's temperature rise and maximum output of 199,000 BTU make it suitable for demanding environments, but users should ensure their home’s infrastructure supports this capacity.

The warranty and support are implied to be robust through Rinnai's recommendation for professional installation and their central app for service and troubleshooting. This tankless water heater is best suited for those needing a high-performance, energy-efficient solution for a large household.

The Rheem RTEX-24 24kW 240V Electric Tankless Water Heater offers a robust solution for continuous hot water supply with its impressive flow rate of up to 5.9 gallons per minute, making it suitable for households with moderate to high hot water demands. One of its standout features is the 99.8% energy efficiency, which helps in reducing energy costs and promoting eco-friendliness. The electric fuel type simplifies installation and maintenance compared to gas models, although it does require a 240V electrical connection, which some homes may need to upgrade to accommodate.

The compact dimensions (17.63”W x 18.25”H x 3.5”D) and wall-mount design make it space-efficient and ideal for small utility areas, while the digital temperature display and ON/OFF dial control provide ease of use and precise temperature adjustments. Additionally, the self-modulating power control enhances efficiency by only using the necessary amount of power based on the water flow rate.

However, the temperature rise might be limited during peak usage in colder climates, potentially requiring additional units for larger homes. Potential buyers should consider the installation requirements and whether their household electrical setup can support the unit. Those looking for a reliable, energy-efficient, and continuous hot water supply will find the Rheem RTEX-24 a compelling option, especially in moderate climates and homes with appropriate electrical infrastructure.

The Rinnai RE199iP is a propane-powered tankless water heater designed for indoor use, offering a strong flow rate of up to 9.8 gallons per minute (GPM). This allows it to comfortably supply hot water to multiple fixtures simultaneously, making it ideal for medium to larger homes requiring consistent hot water. Its heating capacity of 199,000 BTU supports a significant temperature rise, suitable for colder groundwater regions. The unit’s compact dimensions, approximately 14 x 27 inches, facilitate convenient wall mounting without occupying much space.

This model features an energy-saving design that heats water only as needed, which helps reduce utility bills. The LED display is user-friendly, providing service reminders and error codes to assist with maintenance. The heater includes substantial warranty coverage, with 15 years on the heat exchanger, enhancing confidence in its durability. It is important to note that it is a non-condensing unit, making it less energy efficient compared to condensing models that recover additional heat from exhaust gases.

Installation requires professional expertise due to its propane fuel source and high BTU output, involving strict safety measures, so it is not suitable for simple DIY setup. While WiFi control capability is supported, the necessary module must be purchased separately, meaning remote monitoring is not available immediately. Maintenance is straightforward with clear guides and professional service options provided by Rinnai. This model is well-suited for users seeking reliable, high-capacity hot water from a compact propane unit and who are prepared to invest in professional installation. For those prioritizing energy efficiency, especially in mild winter regions, considering a condensing model may be beneficial.