10 Best Compact Tankless Electric Hot Water Heaters 2025 in the United States

The Orbek 18kW tankless electric water heater is a solid choice for those needing a compact and efficient hot water solution for 2 to 3 fixtures at once. It delivers a strong flow rate of up to 4.17 gallons per minute, making it suitable for small to medium household use or point-of-use setups like kitchens and bathrooms. Its power rating of 18kW requires a 240V electrical connection with two dedicated 40A breakers, which means installation needs some electrical know-how or professional help.

The heater excels in energy efficiency by separating the water and electrical components to reduce scaling and corrosion, potentially lowering electricity bills by up to 60% compared to traditional tank heaters. It offers stable temperature control within 1°F, ensuring a comfortable shower experience without sudden changes in water temperature. The LED digital display is easy to read and allows precise temperature settings from 86°F to 140°F. Its compact size is a major plus, saving more than half the space of conventional tank heaters, and it fits neatly in tight indoor spaces. Installation is designed to be straightforward but does require proper wiring and plumbing connections.

The product is ETL certified with multiple safety protections like leakage and over-temperature safeguards, enhancing peace of mind. Customer support includes 24/7 service and a solid warranty, which adds reliability. The specific electrical requirements and the need for two 40A breakers might be a barrier for some users without electrical upgrades. While it supports 2-3 fixtures simultaneously, it may not meet the demand for larger homes with higher hot water needs. This heater is recommended for users who want energy savings, stable temperature, and a space-saving design for small to moderate hot water needs, but it requires proper electrical setup and might not be suitable for very large households.

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 Orbek 14kW tankless electric water heater provides instant hot water with a flow rate of up to 3.38 gallons per minute, suitable for 2 to 3 points of use simultaneously, such as sinks or showers. It includes a stable temperature control system that maintains water temperature within 1°F of the set level, adjustable between 86°F and 140°F through an easy-to-read LED display. Designed for high energy efficiency, it can reduce electricity costs by up to 60% compared to traditional tank heaters, utilizing water-electricity separation technology that also helps prevent scaling and corrosion.

This heater requires a 240V power supply and a dedicated 60-amp breaker, which may necessitate professional electrical installation if your home’s setup is insufficient. Its compact size (approximately 14 by 9.5 inches) saves space, making it ideal for tight installation spots. Safety features include ETL certification and multiple protections against leaks, overheating, dry heating, and electrical issues. The product comes with a warranty and 24/7 customer support for added peace of mind.

Its 14kW power rating limits its use to smaller households or point-of-use applications rather than whole-home coverage. Due to specific electrical requirements and installation considerations, it may not be suitable for those seeking a simple DIY installation or with lower electrical capacity. This model fits well for users needing reliable, energy-efficient instant hot water for a few taps or showers, who have the appropriate electrical setup and want a space-saving solution with modern controls.