10 Best Energy Efficient Electric Water Heater 2025 in the United States

The Rheem RTEX-24 24kW 240V Electric Tankless Water Heater is a robust choice for those seeking energy-efficient hot water solutions. One of its main strengths is its high efficiency, boasting a 99.8% energy efficiency rating, which means it conserves energy effectively. This model offers on-demand, consistent, and continuous hot water, with a maximum flow rate of up to 5.9 gallons per minute (GPM), making it suitable for households with moderate to high hot water needs.

The self-modulating power control is a notable feature, allowing the unit to adjust energy consumption based on the hot water demand, which further supports energy savings. The digital temperature display and ON/OFF dial control provide ease of use and precise temperature settings, enhancing user convenience.

The Rheem 18kW 240V Tankless Electric Water Heater is a compact and modern option for those looking to save energy while ensuring a continuous supply of hot water. One of its standout features is the external digital thermostatic control with an LED display, offering precise temperature management. The advanced self-modulation technology adjusts power usage based on hot water demand, making it more energy-efficient compared to traditional tank heaters.

The durable copper immersion heating elements are a reliable choice, and the heater's flow rate of up to 4.4 GPM is suitable for a small household or moderate usage scenarios. The bottom 3/4 inch NPT water connections and threaded design make installation straightforward, which is a bonus for those who prefer DIY setups.

This unit is a great option for those prioritizing energy efficiency and space-saving designs, though it may not be ideal for larger families requiring simultaneous hot water access.

The Rheem RTGH Series 8.4 GPM Tankless Water Heater is a high-capacity, energy-efficient solution for residential use. Its standout feature is the impressive flow rate of up to 8.4 gallons per minute, making it suitable for households with high hot water demand. It operates on natural gas and has electric ignition for efficient startup. With a maximum temperature setting of 140 degrees Fahrenheit and a default of 120 degrees, it offers flexibility in temperature control.

The unit carries an efficiency rating of 0.93, indicating good energy performance, though it may not be as efficient as other electric models in the same category. One of the significant perks is its robust warranty: 15 years on the heat exchanger, 5 years on parts, and 1 year on labor, providing long-term peace of mind for users. As a tankless water heater, it does not have a tank capacity or first hour rating typical of tank models, which may be a consideration for those accustomed to traditional water heaters.

Additionally, its standby heat loss is minimized due to its tankless design, which can save on energy costs. The compact dimensions (17.7 inches) make it a space-saving option for modern homes.