10 Best Tankless Water Heaters 2026 in the United States

The Rheem RTEX-24 24kW 240V Electric Tankless Water Heater offers a robust solution for continuous hot water supply with its impressive flow rate of up to 5.9 gallons per minute, making it suitable for households with moderate to high hot water demands. One of its standout features is the 99.8% energy efficiency, which helps in reducing energy costs and promoting eco-friendliness. The electric fuel type simplifies installation and maintenance compared to gas models, although it does require a 240V electrical connection, which some homes may need to upgrade to accommodate.

The compact dimensions (17.63”W x 18.25”H x 3.5”D) and wall-mount design make it space-efficient and ideal for small utility areas, while the digital temperature display and ON/OFF dial control provide ease of use and precise temperature adjustments. Additionally, the self-modulating power control enhances efficiency by only using the necessary amount of power based on the water flow rate.

However, the temperature rise might be limited during peak usage in colder climates, potentially requiring additional units for larger homes. Potential buyers should consider the installation requirements and whether their household electrical setup can support the unit. Those looking for a reliable, energy-efficient, and continuous hot water supply will find the Rheem RTEX-24 a compelling option, especially in moderate climates and homes with appropriate electrical infrastructure.

The Rheem RTG-95DVLN-3 is a natural gas tankless water heater designed for indoor use, offering a strong flow rate of 9.5 gallons per minute. This means it can supply enough hot water to run multiple fixtures at once—like a shower and dishwasher—making it suitable for medium to larger households. Its energy efficiency rating of 0.82 is decent for this type of non-condensing model, helping save on energy costs by only heating water on demand. The heater also includes a water-saving setting that claims to save up to 1,100 gallons annually, which is a nice bonus for reducing water waste.

Installation-wise, its compact wall-mounted design (about 13.5 by 24 inches) fits well indoors without requiring much space, but it needs natural gas hookups and venting, so professional installation is recommended. The unit can reach a maximum water temperature of 140°F, which covers typical household needs comfortably. Features like hot-start programming help avoid cold bursts of water by keeping the unit ready, improving user comfort. LeakGuard technology adds a layer of safety by detecting leaks early to prevent damage.

This model is non-condensing, so while it is efficient, it’s not as efficient as condensing units that recover more heat. With mostly positive user reviews averaging 4 out of 5 stars, the Rheem water heater offers a reliable, energy-conscious choice for those looking to upgrade from traditional tank heaters without the complexity of a condensing system.

The Stiebel Eltron 239223 Tempra 29 Plus is an electric tankless water heater offering an efficient and reliable solution for on-demand hot water. One of its most notable strengths is its ability to provide a continuous and unlimited supply of hot water, making it ideal for households with high hot water demands. With a sleek and compact design, it saves space and does not require venting, which simplifies the installation process.

Additionally, it features two temperature memory presets for personalized adjustment and an LED display for easy monitoring. However, the installation requires a hard-wired 240 or 208-volt electric service and three separate dedicated 40 amp breakers with 8 gauge copper wiring, which could be a drawback for homes not already equipped with this setup. It has a maximum draw of 28,800 watts at 240 volts or 21,600 watts at 208 volts, emphasizing its substantial power requirement.

The maximum flow rate is 3 gallons per minute, which may be limiting if multiple hot water outlets are used simultaneously. Certified by CSA, NSF, UL, and ANSI, it ensures safety and reliability. At 24 pounds and dimensions of 16.63 inches wide by 14.5 inches high, it is relatively easy to install and manage. Given its high power capacity and specific installation requirements, this water heater is best suited for larger homes or those with significant hot water needs and an adequate electrical setup.