SoCalGas Demonstrates North America’s First 100% Hydrogen-Powered Tankless Water Heater

Nov 4, 2025

SoCalGas has successfully powered up North America’s first 100% hydrogen-fueled tankless water heater, marking an important step in exploring hydrogen’s future role as a zero-carbon energy source for residential use. The demonstration is part of SoCalGas’ broader efforts to support the advancement of decarbonized energy technologies.

Developed and provided by Rinnai Corp., the prototype unit was installed and tested at SoCalGas’ Engineering Analysis Center (EAC) in Pico Rivera, Calif. SoCalGas engineers have demonstrated that the unit performs safely and reliably, heating water using only hydrogen as fuel. The unit is not yet commercially available.

Unlike traditional water heaters that store hot water in a tank, tankless water heaters heat water only when needed, offering greater energy efficiency and space savings.

The demonstration serves as a proof of concept to explore how pure hydrogen combustion technology could potentially be applied in residential settings in the future.

The research demonstration has enabled engineers to collect and analyze data to evaluate safety protocols for hydrogen appliances, while monitoring the unit’s efficiency, performance and emissions. This data is being shared with Rinnai to support the future development of end-use hydrogen appliances.

“This collaboration with Rinnai is a great example of how we’re helping advance the development of hydrogen technology,” said SoCalGas Manager of Energy Programs and Strategy Darren Hanway. “We’re proud to support innovation that could potentially help reduce carbon emissions and expand efficient energy options for customers.”

Because hydrogen produces zero carbon emissions when burned, with water vapor as its primary byproduct, it holds promise as a key component in achieving a carbon-neutral future. SoCalGas is conducting research projects like this one to help lay the foundation for safe, reliable, and scalable hydrogen applications.

The EAC serves as SoCalGas’ primary laboratory for hydrogen research. Engineers there have conducted a wide range of demonstrations, including appliance safety assessments, leak detection studies, compressor performance evaluations, and materials compatibility research.

One notable initiative at the EAC is the Living Lab project, a NYSEARCH and SoCalGas RD&D collaboration which examines the impacts of higher concentrations of blended hydrogen on gas piping materials and various aspects of gas engineering and operations. By simulating real-world conditions, the project helps advance understanding of hydrogen blending infrastructure and its potential role in future energy systems.

SoCalGas is committed to delivering safe, reliable and affordable energy today, while exploring solutions that make us ready for tomorrow.

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About SoCalGas
SoCalGas is the largest gas distribution utility in the United States, serving more than 21 million consumers across approximately 24,000 square miles of Central and Southern California. Our mission is: Safe, Reliable, and Affordable energy delivery today. Ready for tomorrow. SoCalGas is a recognized leader in the energy industry and has been named Corporate Member of the Year by the Los Angeles Chamber of Commerce for its volunteer leadership in the communities it serves. SoCalGas is a subsidiary of Sempra (NYSE: SRE), a leading North American energy infrastructure company. For more information, visit SoCalGas.com/newsroom or connect with SoCalGas on social media @SoCalGas.

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Sempra Infrastructure, Sempra Infrastructure Partners, Sempra Texas, Sempra Texas Utilities, Oncor Electric Delivery Company LLC (Oncor) and Infraestructura Energética Nova, S.A.P.I. de C.V. (IEnova) are not the same companies as the California utilities, San Diego Gas & Electric Company or Southern California Gas Company, nor are they regulated by the CPUC.