Vaillant Group says its Hohenwart heating project in Bavaria has moved beyond the pilot phase. Renamed H2Dahoam, it is presented by the company as Germany’s first hydrogen network in permanent regular operation. The project is testing whether existing local heating infrastructure and adapted household boilers can continue supplying homes when natural gas is replaced by hydrogen.
Hohenwart is a municipality of around 5,000 residents. In the participating neighborhood, heating has switched from natural gas to hydrogen. During the earlier H2Direkt phase, ten detached or semi-detached homes and one commercial operation were supplied entirely with green hydrogen, according to Vaillant. <Vaillant Group’s account of the project>
Hydrogen is using the existing local network
The hydrogen travels through the network already serving the participating properties. That is the project’s most direct implication for heating infrastructure: the trial does not rely on building a separate local distribution network for these homes.
The heating equipment was adapted around existing boiler technology. Vaillant says its appliances designed for operation with 100% hydrogen ran reliably through two complete heating periods. The test units were converted into series-production ecoTEC plus VC gas-condensing appliances, while a conversion kit enables operation with 100% hydrogen.
For participating households, the changes were limited apart from the heat generator and flue-gas system. Vaillant says only a few components needed to be adapted. One participating family lives in a detached house of roughly 186 square metres, built in 2020, and has used hydrogen heating since the project began. The family expects its heating costs to remain broadly comparable with gas.
The project now moves toward local hydrogen production
With the funding period over, Energie Südbayern GmbH remains the supplier, Energienetze Bayern GmbH the network operator and Vaillant Deutschland the technology partner. The next planned phase adds local production and storage of green hydrogen. The project is then expected to expand gradually, with a long-term vision of reaching up to 50% of connected households.
That plan changes the question from whether a small group of properties can use hydrogen to whether the local system can produce, store and distribute enough of it for a larger customer base. The published information does not quantify the amount of hydrogen involved or promise a specific expansion date, so the 50% figure remains a long-term vision rather than a confirmed rollout target.
What this means for homeowners
For energy-conscious homeowners, H2Dahoam points to compatibility and continuity rather than an automatic reduction in heating bills. The participating family’s expectation suggests costs broadly comparable with gas, but the project’s published facts provide no quantified saving. The practical appeal is instead the possibility of reusing an existing network and limiting changes inside the home to the heat generator, flue-gas system and a few related components.
That conclusion remains specific to Hohenwart and to the equipment used in the project. The next meaningful test will be the planned local hydrogen production and storage, followed by the ability to extend service beyond the initial ten homes, one commercial operation and their existing network.
Hohenwart has therefore moved hydrogen heating into regular operation, while the wider promise is still conditional. The project demonstrates continuity of infrastructure and household equipment; its broader relevance will depend on how the planned production, storage and expansion stages perform.