10 Best Electric Tankless Water Heater 2025 in the United States

The Stiebel Eltron 239223 Tempra 29 Plus is a high-performing electric tankless water heater that provides an on-demand and continuous supply of hot water. It features a sleek, space-saving design and does not require venting, which makes it versatile for various home installations. This model has a maximum flow rate of 3 gallons per minute (GPM), making it suitable for households with moderate hot water needs.

Its power rating is substantial, operating at 28.8 kW, which ensures a quick temperature rise but also means it requires a significant electrical setup: 240-volt service, three dedicated 40 amp breakers, and at least 200 amp total service to the home. This could be a hurdle for some installations and might require professional electrical work to update the home's capacity.

The unit features two temperature memory presets, providing convenience for users with different hot water preferences. It also has a useful LED display for easy monitoring and adjustments. Energy efficiency is a highlight, as tankless systems generally save on energy compared to traditional tank heaters by only heating water as needed. Potential buyers should consider the installation requirements carefully. This unit is most beneficial for medium to large households that can support the electrical demands, and who are looking for a reliable, space-saving, and energy-efficient solution for their hot water needs.

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 EcoSmart ECO 11 Electric Tankless Water Heater is a compact and energy-efficient option for providing hot water on demand. With a power rating of 13KW at 240 Volts, it is ideal for smaller applications like a bathroom, small sink, or an office breakroom. This unit can deliver between 1.3 and 3.1 gallons per minute depending on the inlet water temperature, ensuring a consistent supply of hot water within 1 degree of the selected temperature, thanks to its patented self-modulating technology.

The heater is highly energy-efficient, boasting a 99% thermal energy efficiency, and heats water only when needed, which can contribute to reduced energy bills. Additionally, its compact size (11.5 x 8 x 3.75 inches) allows for flexible installation, either mounted on a wall or used at the point of use, saving valuable space compared to traditional tank heaters. However, the unit has a high amperage draw of 54 A, which may require electrical upgrades in some homes.

It is also worth noting that while the product comes with a lifetime warranty on various components, it does not cover labor or incidental damages. This water heater is best suited for individuals or small families needing a dedicated hot water source for specific low-flow applications.