The Best Tankless Water Heaters of 2025

The Stiebel Eltron Tempra 36 Plus tankless water heater is an all-electric unit designed to support the needs of an entire house. At a flow rate of up to 7.5 gallons per minute, this heater can easily accommodate four or more appliances and fixtures operating simultaneously. The electric heating system runs with virtually no sound, providing on-demand hot water right away.

Like most tankless systems, the Siebel Tempra 36 Plus is estimated to save between 15 and 20% on home energy bills by eliminating heat loss from a standing tank. If your home doesn't have the option for natural gas heaters, then this electric system is a solid replacement.

Rinnai is one of the top names in tankless water heating, and their RU160iN unit demonstrates why. These small units save massive amounts of space and energy consumption over a traditional water heater without sacrificing performance. The RU160iN can support anywhere from three to seven appliances or fixtures simultaneously, depending on their individual draw, providing up to nine gallons per minute of hot water.

The built-in recirculation technology offers even faster hot water and can be configured to match your daily usage habits. This tankless water heater, which runs on natural gas and should be installed by a licensed professional, is robust enough to support most people's at-home water needs.

The ECO 36 tankless water heater is an electric unit with the capacity to support your whole home's water needs. The 36-kilowatt heater can provide between 3.6 and 8.7 gallons per minute. This can support between two and five appliances running simultaneously while saving significant money on your energy bills. The ECO 36 is designed to self-regulate, using only the energy needed to heat the water when you need it. And because it's all-electric, this is a great unit to use in locations that don't have access to natural gas.

The Rinnai RL75eN water heater is designed for installation outdoors, freeing up space in your utility room or basement. This unit, powered by natural gas, has a flow rate of up to 7.5 gallons per minute, enough to support up to four different appliances or fixtures simultaneously.

It's robust enough that you can shower, do dishes, wash hands, and run the laundry all at the same time. Rinnai's Wi-Fi controls make adjustments simple and easy, and the recirculation technology brings warm water faster. For those with moderate water use who want the unit installed outside, this is an ideal solution.

The Rheem 240V RTEX-13 residential tankless water heater is a quality point-of-use hot water heater. With a 3.17GPM flow rate, it's designed to support one to two appliances in a single location, such as a shower in the bathroom.

This is an excellent option for supplying an expansion or addition to your home's existing infrastructure. The digital temperature display and exterior controls make raising or lowering the heat between 80 and 140 degrees Fahrenheit easy. Installation is relatively simple, but should still be left to professionals in most cases, since this is dealing with both water lines and electricity. If you're looking for a small tankless water heater, then this is a quality option.

The Camplux 2.64 GPM propane water heater is designed specifically for low-use outdoor applications. Perfect for sheds, outdoor showers, or campers and RVs, this tankless water heater can support one or two appliances at a time.

It connects easily and securely to standard propane tanks, with numerous safety features like anti-freezing, automatic gas shut offs, and overheating protection. It's designed with efficiency in mind—the manufacturer claims an 11.5% energy savings from the improved combustion chamber and heat exchangers. For small-use applications or families on a road trip, this is an elegant solution.