10 Best Compact Tankless Electric Hot Water Heaters 2026 in the United States

The EcoSmart ECO 27 is a compact, wall-mounted electric tankless water heater that stands out for its high power rating of 27 kW, which allows it to deliver a maximum flow rate of about 6.6 gallons per minute. This means it can supply enough hot water for multiple bathroom fixtures simultaneously in small to medium homes, making it suitable if you want a reliable flow without a bulky tank. It uses 240 volts on a single phase and offers digital temperature control with an easy-to-read LED display, so adjusting hot water temperature up to 120°F is straightforward. The heater is quite space-efficient with dimensions of 17 by 17 by 3.5 inches and weighs just under 11 pounds, which makes installation feasible in tight spots, especially compared to traditional tank water heaters. Energy efficiency is a strong point here; as a tankless unit, it heats water on demand, helping reduce energy waste and utility bills. EcoSmart backs this model with a limited lifetime warranty on key electronic components and heating elements, though the warranty doesn’t cover labor or incidental costs and requires proper registration to remain valid.

One limitation is that the maximum temperature is capped at 120°F, which might be lower than some users expect for specific needs. Also, while the flow rate is good for many households, it might be insufficient for larger homes with higher simultaneous hot water demands. The EcoSmart ECO 27 represents a smart choice if you want compact size, energy-efficient electric heating, and moderate hot water flow, but it may not be the best fit if you need very high temperature settings or serve a larger family with heavy water usage.

The Rheem RTEX-36 is a powerful electric tankless water heater designed for indoor wall mounting. It delivers up to 6 gallons per minute, sufficient to supply hot water for multiple fixtures at once in moderate-sized homes. With a 36 kW power rating and 240V voltage, it can provide a strong temperature rise, heating water quickly and efficiently. Its energy efficiency is excellent at 99.8%, meaning very little energy is wasted during operation, which can help save on electricity bills over time. The unit features digital temperature control, allowing you to set your preferred water temperature precisely for added convenience and comfort. It has a compact and sleek silver design, but is fairly heavy at around 24 pounds and needs to be hardwired with a 240V power supply, so professional installation is recommended.

The size is manageable for most indoor utility spaces, but you’ll want to ensure your electrical system can support its power needs. Customer feedback highlights its reliability and strong performance. This model may be more suitable for users with moderate to high hot water demand rather than very small households or low-demand applications due to its higher power and flow capabilities. The RTEX-36 is ideal for those seeking an energy-efficient tankless heater capable of handling multiple water outlets simultaneously, provided they have the appropriate electrical setup and installation space.

The EcoSmart ECO 11 is a compact and efficient tankless electric water heater designed mainly for small applications like a bathroom, office sink, or breakroom. It delivers a flow rate between 1.3 and 3.1 gallons per minute, which is suitable for low-flow needs but won’t support multiple large water outlets simultaneously. Its 13,000-watt power rating and 240-volt operation enable it to heat water consistently with a temperature control accurate within 1 degree, reaching up to 140°F. One of its standout features is the patented self-modulating technology, which adjusts energy use based on your hot water demand, making it very energy efficient at about 99%, and helping you save on electricity bills.

The unit is also notably small—about 11.5 by 8 inches—and wall-mounted, saving valuable space compared to traditional tank heaters. Installation is straightforward for point-of-use situations, but because it draws 54 amps, your electrical system must be compatible and may need professional setup. The ECO 11 includes a lifetime warranty on the electronics and heating elements, which adds peace of mind, though labor costs aren’t covered.

Due to its limited flow rate, this model is best suited for single fixtures rather than whole-house use, and the relatively high amperage requirement can complicate installation in some homes. For those needing a compact, energy-saving unit for small or occasional hot water needs, this product provides reliable and consistent performance with easy temperature control.