10 Best Tankless Water Heaters 2026 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 RX180iN is a powerful and versatile tankless water heater designed to provide continuous hot water for medium to large households. It delivers up to 10 gallons per minute, which means it can handle multiple fixtures at once, such as showers and sinks running simultaneously. This high flow rate is suitable if you have a busy home or want to avoid running out of hot water during peak times. It runs on natural gas or propane, giving you flexibility depending on your energy source, and it has a very high energy efficiency rating (UEF 0.98), which helps reduce utility costs compared to traditional water heaters. The compact size (about the size of a small suitcase) and indoor or outdoor installation options add convenience, although outdoor installation requires a specific vent cap.

Professional installation is recommended due to the technical nature of gas hookups and venting requirements. Maintenance is made easier with features like a Quick Flush, which helps keep the system clean and running smoothly, though periodic servicing by a technician will still be necessary. The unit operates quietly and includes smart controls compatible with WiFi modules (sold separately), allowing for remote monitoring and adjustments.

The initial cost and installation complexity can be higher than standard tank heaters, and it requires a 120-volt power supply mainly for controls rather than heating. If your home needs a reliable, efficient, and space-saving water heating solution with the ability to supply multiple fixtures simultaneously, the Rinnai RX180iN is an excellent choice.