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

The Rheem RTEX-24 24kW 240V Electric Tankless Water Heater offers a strong performance with a maximum flow rate of 5.9 GPM. This flow rate is suitable for small to medium-sized households, enabling the heater to supply hot water to multiple fixtures simultaneously.

The device is equipped with an ON/OFF dial control and a digital temperature display, making it user-friendly. The self-modulating power control adjusts energy usage based on hot water demand, enhancing efficiency and contributing to its impressive 99.8% energy efficiency rating.

This makes it an economical choice for those concerned with energy consumption and cost savings. Installation is straightforward with bottom 3/4.

The Rheem 18kW 240V Tankless Electric Water Heater is a robust option for those seeking an efficient, portable hot water solution. With a flow rate of up to 4.4 GPM, it can handle moderate hot water demands, making it suitable for small to medium-sized homes or apartments. The 18kW power output ensures a consistent and substantial temperature rise, providing reliable hot water performance.

Its compact size (14.5"W x 18.25"H) enhances its portability, allowing it to fit in various spaces without much hassle. The installation process is straightforward due to the bottom 3/4 inch NPT water connections and threaded design for easy replacement, making it user-friendly for those who prefer a DIY approach. Additionally, the external digital thermostatic control with LED display offers precise temperature regulation, ensuring comfort and safety.

However, while the copper immersion heating elements are durable and serviceable, the energy efficiency could be a concern for some users, especially those with high electricity rates. It is important to note that while installation is simple, professional installation is recommended to ensure optimal performance and safety. In summary, this water heater is a reliable and user-friendly option for individuals or families needing an efficient, portable hot water solution with easy installation and precise temperature control.

The Stiebel Eltron Tempra 29 Trend Tankless Water Heater is designed to provide continuous, on-demand hot water without interruptions. With a power rating of 28.8 kW, it can supply a consistent stream of hot water, making it suitable for whole-house use. The flow rate is not explicitly mentioned, but given its kW rating, it should handle moderate to high demands effectively. It offers a substantial temperature rise, with output water temperatures ranging from 68° to 140°F, which caters to various household needs.

Its compact size (16.63"W x 14.5"H) and sleek design make it space-efficient and visually unobtrusive, fitting well in small areas. The unit operates silently, which is a significant advantage for maintaining a peaceful environment. Installation requires a minimum recommended electric service of 200 A, which might necessitate an upgrade in older homes. No venting is required, simplifying the installation process.

The water heater comes with impressive safety features, including auto-modulation for energy savings and solid copper heating components, ensuring durability and reliability. Energy efficiency is emphasized through its eco-friendly design, making it a good choice for reducing energy consumption. The digital temperature display is user-friendly, and the product is backed by robust warranties (7-Year Leakage and 3-Year Parts). However, the significant power requirement might be a limitation for some households, and potential buyers should verify their electrical capacity before purchase. The Tempra 29 Trend offers reliable performance, efficient energy use, and ease of installation, making it a compelling option for those in need of a portable tankless electric hot water heater.