10 Best Electric Tankless Water Heater 2026 in the United States

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.

The Stiebel Eltron Tempra 24 Trend is a powerful electric tankless water heater designed to deliver continuous, on-demand hot water without the interruptions common in traditional systems. With a strong 24 kW (18000 watts) power rating running on 240 volts, it can provide ample hot water for most whole-house needs, especially in homes with moderate demand. Its advanced electronic controls and auto-modulation technology help optimize energy use by adjusting power based on flow, which can reduce electricity costs compared to older models.

The water temperature range (68° to 140°F) offers good flexibility for various household uses, and the digital LED display makes setting and monitoring water temperature easy. The heater is compact and wall-mounted, making it suitable for homes with limited space and simplifying installation since no venting is required. However, it requires a minimum recommended electric service of 150 amps, so it may not be compatible with all home electrical systems without upgrades. Also, while the unit is designed for high efficiency, very large households with multiple simultaneous showers might find its flow rate limits a bit restrictive.

Customers generally praise its quiet operation and reliability, supported by a solid 7-year leakage warranty and 3-year parts warranty, which adds peace of mind. This model is well suited for those seeking a space-saving, energy-efficient electric water heater that delivers consistent hot water and can handle a typical family’s daily needs, provided your electrical system supports it.