10 Best Electric Tankless Hot Water Heater 2025 in the United States

The Stiebel Eltron Tempra 29 Trend is an electric tankless water heater designed for those seeking a continuous supply of hot water. One of its standout features is the ability to provide on-demand hot water, which means no more unexpected cold showers. With a flow rate of up to 9.5 gallons per minute, it can serve an entire household, making it ideal for families or homes with high water usage needs.

In terms of energy efficiency, this unit is a strong contender. Its sleek design not only saves space but also incorporates auto-modulation technology to minimize energy use when hot water is not needed. This makes it a great eco-friendly choice for environmentally conscious consumers. The silent operation further enhances its appeal, as it won't disrupt your home environment while in use.

The Tempra 29 Trend requires a significant electrical service of at least 200 amps, which may necessitate an upgrade to your home’s electrical system if it currently does not meet this requirement. Additionally, while it has a good warranty (7 years for leakage and 3 years for parts), some users may still worry about the initial installation costs and the need for professional setup. The digital temperature display is a convenient feature, allowing users to monitor their water temperature easily. It's compact at 16.63 inches wide and 14.5 inches high, making it suitable for various installation spaces. Potential buyers should verify that their plumbing can support a tankless unit effectively. The Stiebel Eltron Tempra 29 Trend serves as an excellent choice for those looking for reliable, efficient hot water solutions, particularly in larger households, while being mindful of the electrical demands and installation considerations that come with such a high-performance unit.

The Rheem 18kW 240V Tankless Electric Water Heater is designed to offer an on-demand hot water solution for homeowners looking to save space and energy. With a flow rate of up to 4.4 gallons per minute (GPM), it can efficiently supply hot water for multiple outlets at once, making it suitable for medium-sized households or apartments. One standout feature is its external digital thermostatic control with a precise +/- 1 degree accuracy, allowing users to easily set their desired water temperature.

The self-modulation technology adjusts the power based on your hot water needs, optimizing energy use and maintaining efficiency, which is an impressive 99.8%. This means you can enjoy hot water without worrying too much about energy bills.

Installation is relatively straightforward with its wall-mount design and 3/4 inch NPT connections which simplify the setup process. The durable copper heating elements are also field-serviceable, contributing to the unit’s longevity. There are a few drawbacks to consider. The unit requires a 240V power supply and an adequate electrical setup, which might necessitate professional installation if your home isn’t equipped. It may not be powerful enough for larger households or homes with high demand for simultaneous hot water use.

The EcoSmart ECO 11 Electric Tankless Water Heater is designed to provide endless on-demand hot water, making it ideal for small-scale applications like a bathroom, small sink, or office breakroom. One of its main strengths is its compact size, being 90% smaller than traditional tank heaters, which allows it to be installed on a wall or at the point of use, saving significant space. Additionally, its energy efficiency is notable at 99%, as it only heats water when needed, unlike traditional heaters that maintain water temperature continuously, potentially leading to energy savings over time.

The patented self-modulating technology ensures that the water temperature remains consistent within 1 degree of the selected temperature, enhancing user comfort and efficiency. With a flow rate of up to 3.1 gallons per minute, it is suitable for low-flow applications and can provide consistent hot water for its intended uses. However, its power requirements are quite high, requiring 240 volts and a 54-amp draw, which might necessitate electrical upgrades for some homes.

Also, while it has a lifetime warranty on electronics, exchanger, and element, this warranty only covers the cost of the heater and not labor or any incidental damages, which could be a consideration for some users. The EcoSmart ECO 11's energy efficiency and compact size make it a strong contender for those looking for a space-saving, on-demand hot water solution for smaller applications. However, potential buyers should be aware of the electrical requirements and limited warranty coverage.