10 Best high efficiency tankless electric hot water heaters 2026 in the United States

The Rheem RTEX-24 24kW 240V Electric Tankless Water Heater offers an impressive flow rate of up to 5.9 gallons per minute (GPM), which is quite strong for most household needs. Its self-modulating power control ensures efficient energy use by adjusting power based on hot water demand, contributing to its notable 99.8% energy efficiency.

The adjustable digital temperature display with an ON/OFF dial control makes it user-friendly, allowing for precise temperature adjustments and easy monitoring. Installation should be straightforward with its compact size (17.63”W x 18.25”H x 3.5”D) and wall-mount design, although professional installation is recommended due to the 24kW power requirement and 240V voltage. The unit's weight of 17.8 pounds is manageable for most installation scenarios.

Durability is supported by the stainless steel finish and robust build. The maximum water pressure of 150 PSI should be checked against your home’s water pressure to ensure compatibility. This heater is well-suited for homeowners looking for an efficient, high-performing solution to provide continuous hot water on demand.

The Rheem 11kW 240V Tankless Electric Water Heater is a compact and efficient option for delivering on-demand hot water. One of its strengths is the adjustable digital temperature display and ON/OFF dial control, making it user-friendly. The heater's self-modulating power control helps in maintaining energy efficiency, which is crucial for reducing electricity bills.

With a flow rate of up to 2.68 GPM, it can provide continuous hot water, suitable for small to medium households or point-of-use applications like sinks and showers. Its compact size (8.25"W x 12.63"H) and wall-mount installation make it a space-saving option, fitting well in tight spaces. However, the power requirement of 240V and 11kW might necessitate an electrical upgrade if your existing system isn't compatible, which could be an additional cost.

The maximum temperature rise might not be sufficient for larger households needing simultaneous hot water at multiple outlets. With a solid customer rating of 4.1 out of 5 stars from 375 reviews, users generally seem satisfied with its performance. A notable plus is the LED display, which enhances usability. The product's weight is just 7.04 pounds, making it relatively easy to handle during installation. This heater is best suited for smaller homes or individual usage points, ensuring energy efficiency and consistent performance.

The Stiebel Eltron Tempra 36 Plus is a high-powered tankless electric water heater designed to deliver continuous hot water on demand. It operates at 27,000 watts with a maximum flow rate of 1.5 gallons per minute, which is suitable for smaller households or point-of-use setups but might be limiting if you need simultaneous hot water at multiple fixtures. Its advanced flow control and self-modulation technology help save energy by adjusting power use based on demand, making it a strong choice if you're looking to reduce utility bills.

The digital LED display allows for precise temperature control, which adds convenience and helps maintain consistent water temperature. Installation is straightforward with a floor mounting method, and the unit is relatively compact at about 17 by 14.5 inches, so it won’t take up much space. However, it requires a 208-volt power supply, which might need electrical upgrades in some homes. The product is well-reviewed for reliability and efficiency.

If you want an energy-efficient electric tankless heater for a smaller capacity setting and don’t mind the electrical requirements, the Tempra 36 Plus represents a solid, dependable option.