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 Rheem 8kW 240V Tankless Electric Water Heater is a compact and efficient choice for those needing on-demand hot water in small households, cabins, or point-of-use applications like a single bathroom or kitchen sink. Its flow rate of up to 1.95 gallons per minute (GPM) means it can comfortably supply hot water for light usage, but it may struggle to keep up with multiple fixtures running simultaneously. This model uses electricity, which makes it cleaner and easier to install compared to gas-powered units, especially if you don't have a gas line nearby. The unit’s size is quite small (about 8.25 by 12.63 inches), so it fits well in tight spaces and mounts easily on a wall. Rheem includes an adjustable digital temperature display with a simple dial control, letting you precisely manage water temperature, which adds convenience and energy savings through its self-modulating power feature.

In terms of installation, it requires a 240V electrical connection and proper water pressure, which might need a qualified electrician and plumber. Maintenance is relatively low, but like any tankless heater, it can require occasional descaling in areas with hard water to keep it running smoothly. While this model is not suited for large families or high-demand situations due to its moderate flow rate, it provides reliable, continuous hot water with good energy efficiency for smaller needs.