10 Best Tankless Water Heaters 2026 in the United States

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 18kW 240V Tankless Electric Water Heater is a compelling option for those looking for an efficient, easy-to-install solution for their hot water needs. One of its standout features is the external digital thermostatic control with an LED display, which offers precise temperature control with +/- 1 degree accuracy. This makes it user-friendly and ensures you always get the perfect water temperature.

Its advanced self-modulation technology is another highlight, as it adjusts power usage based on your hot water demand, contributing to energy efficiency and potentially reducing your energy bills over time. The unit's flow rate is up to 4.4 gallons per minute (GPM), which should be sufficient for small to medium households but might not meet the demands of larger families with high simultaneous water usage.

The heater uses durable copper immersion heating elements that are field-serviceable, enhancing its longevity and ease of maintenance. Installation is straightforward with bottom 3/4 inch NPT water connections and threaded design, making it simple to replace existing water heaters. The compact size (14.5 inches wide and 18.25 inches high) allows it to fit in tight spaces, adding to its versatility. However, as an electric unit, it may not be as powerful as gas models in terms of temperature rise, especially in very cold climates.

The Noritz GQ-C3261WX-FF US NG EZ Series Pro is a natural gas tankless water heater designed for residential use, delivering a strong flow rate of 11.1 gallons per minute (GPM). This means it can supply enough hot water for several fixtures at once, making it suitable for medium to large households. It heats water up to 140°F, providing a good temperature rise for most home needs. Running on natural gas ensures energy-efficient operation, and the 199,900 BTU output supports consistent performance.

The unit is compact with dimensions of about 12 x 18 x 26 inches and weighs around 77 pounds, making it fairly manageable for wall mounting indoors or outdoors. Installation requires proper gas and venting setup, so professional help is recommended to ensure safety and optimal operation. One modern feature is Bluetooth connectivity, allowing users to monitor and adjust settings conveniently from a smartphone app.

On the maintenance side, like most tankless heaters, it will need periodic flushing to prevent mineral buildup, especially if you have hard water. The high efficiency rating suggests it can help reduce energy bills compared to traditional tank heaters. It relies solely on natural gas supply. If you want a reliable, efficient gas-powered tankless water heater with smart features and a solid flow rate, this Noritz model is a strong choice for homeowners who want to save space and energy.