10 Best Electric Tankless Water Heater 2026 in the United States

The Rinnai RX130iN is a compact, high-performance tankless water heater that runs on natural gas or propane instead of electricity. It delivers a solid flow rate of up to 7.1 gallons per minute, meaning it can comfortably supply hot water to about four fixtures at once, suitable for medium to large households. With a power rating of 130,000 BTU and the ability to heat water up to 140°F, it provides sufficient temperature rise to meet most residential hot water needs. One of its standout features is its high energy efficiency with a UEF (Uniform Energy Factor) of 0.97, helping reduce energy costs compared to traditional tank heaters.

Its stainless steel construction and compact size (about 19" wide by 31" high) allow for flexible wall mounting indoors or outdoors, though outdoor installation requires an additional vent cap. The heater includes smart controls and WiFi compatibility for easy operation and monitoring, but professional installation is recommended to ensure safety and optimal performance. While it is not electric, it uses minimal electrical power (47 watts) mainly for controls and ignition.

The 15-year heat exchanger warranty reflects the brand’s confidence in durability, but the warranty requires timely product registration. This unit is well suited for users wanting a reliable, efficient gas-powered tankless water heater that saves space and provides continuous hot water without running out. The need for professional installation and specific venting options might add complexity and cost, making it less ideal for those seeking a simple DIY setup.

The Rheem RTEX-24 Electric Tankless Water Heater offers a powerful solution for those seeking on-demand hot water. With a 24kW power rating and a maximum flow rate of 5.9 gallons per minute, it is capable of providing continuous hot water for multiple applications simultaneously. The self-modulating power control is a standout feature, allowing for energy-efficient operation by adjusting the power usage based on the actual demand. Additionally, its energy efficiency rating of 99.8% ensures minimal energy wastage, which can lead to lower utility bills over time.

The digital temperature display and ON/OFF dial control make it easy to adjust and monitor the temperature settings, enhancing user convenience. The compact size (17.63 inches wide, 18.25 inches high, and 3.5 inches deep) and wall-mount installation method make it suitable for homes with limited space. However, it is important to note that the unit requires a 240V electrical connection and professional installation is recommended to ensure optimal performance and safety.

While it is a highly efficient and effective water heater, its performance may vary depending on the incoming water temperature and the number of simultaneous hot water demands. Given its robust features, the Rheem RTEX-24 is well-suited for households looking for a reliable and efficient electric tankless water heater but may not be ideal for larger homes with high hot water consumption.

The Rheem 18kW 240V Tankless Electric Water Heater is a solid choice for those looking for an efficient and space-saving water heating solution. One of its standout features is the impressive flow rate of up to 4.4 gallons per minute (GPM), which makes it suitable for smaller households or apartments where demand for hot water isn't excessively high. Its energy efficiency rating of 99.8% is quite remarkable, meaning you'll likely save on your energy bills compared to traditional tank heaters. The self-modulation technology adjusts the power based on hot water demand, which further optimizes energy use.

The external digital control with an LED display is user-friendly, allowing for precise temperature settings within a +/- 1-degree accuracy. This feature is particularly beneficial for those who want to maintain consistent hot water temperatures. The installation is straightforward as well, with bottom connections that make it easier to replace or service when needed.

There are a few drawbacks to consider. While the 4.4 GPM flow rate is adequate for smaller setups, larger families or homes with multiple bathrooms may find it insufficient during peak usage times. Additionally, being an electric unit, it may not be the best option for locations where electricity supply is unreliable or insufficient to support its high wattage of 18,000 watts. Lastly, while the unit is compact, its installation does require adequate space and professional help, especially for wall mounting, which could be a consideration for DIY enthusiasts.