10 Best Electric On Demand Water Heater 2026 in the United States

The Rheem RTEX-24 Electric Tankless Water Heater is a solid choice for those looking for on-demand hot water. With a power output of 24kW and a flow rate of up to 5.9 gallons per minute (GPM), it offers consistent and continuous hot water supply, making it suitable for medium to large households.

The adjustable digital temperature display and self-modulating power control add convenience and efficiency, allowing users to customize their water temperature easily. Its 99.8% energy efficiency rating means it is environmentally friendly and could help in lowering energy bills over time.

The LED display is an added feature that enhances user experience by providing clear temperature readings. Installation is straightforward, thanks to the wall mount design and 3/4

The Rheem 18kW 240V Tankless Electric Water Heater is a solid option for those looking to efficiently supply hot water on demand. With a flow rate of up to 4.4 gallons per minute (GPM), it can cater to smaller households or applications requiring moderate hot water supply, making it ideal for apartments or homes with limited space.

One of its strengths is the 99.8% energy efficiency, which means it consumes less energy compared to traditional water heaters. This can help save on electricity bills over time. The unit features an external digital thermostatic control with an LED display, allowing users to set temperatures with +/- 1 degree accuracy, which is a handy feature for precise control and comfort. The self-modulating technology adjusts the power based on the demand for hot water, ensuring consistent performance. Additionally, the durable copper immersion heating elements are field-serviceable, which can simplify maintenance and repair.

However, there are some limitations to consider. The maximum flow rate of 4.4 GPM may not be sufficient for larger households or simultaneous high-demand situations, such as running multiple showers at once. Also, while the installation is straightforward with bottom water connections, it may still require professional assistance for optimal setup, especially for those unfamiliar with plumbing. It’s also worth noting that while the product dimensions are compact (14.5 inches wide and 18.25 inches high), its wall-mounted design might not suit every installation preference.

The Stiebel Eltron Tempra 36 Plus is a powerful electric tankless water heater delivering 36 kilowatts of heating power, which is quite high for on-demand water heating. It provides a flow rate of about 1.5 gallons per minute, making it suitable for smaller households or limited simultaneous hot water needs, but it might struggle to supply multiple large fixtures at once, like several showers running simultaneously. Thanks to its advanced flow control and self-modulation technology, it adjusts energy use based on demand, helping to save on electricity bills by avoiding unnecessary heating.

You can precisely set the temperature using its digital LED display, with a maximum output temperature of 140°F, which covers most household needs. Its compact wall-mounted design (about 16.6 by 14.5 inches) makes it space-efficient, but installation requires hard wiring and professional help, which adds to initial setup complexity. Made with copper components and featuring high energy efficiency, it supports smart home integration, which can be handy if you want remote control or monitoring.

This model is well-suited for those seeking an energy-efficient, compact electric on-demand heater for small to medium water demands. However, it may not be ideal if you require hot water for many fixtures at the same time.