The H2Dahoam project marks the first time a hydrogen network has entered regular operation in Germany . In Hohenwart, Upper Bavaria, the network is set to supply several private households and a commercial business with 100 percent hydrogen via an existing gas infrastructure .
In addition to Vaillant Germany, the gas distribution network operator Energienetze Bayern GmbH & Co. KG and the energy service provider Energie Südbayern GmbH are also involved in the project.
H2Dahoam is based on H2Direkt
This project builds on the H2Direkt research and pilot project, which over the past two years demonstrated the technical feasibility of supplying hydrogen to existing buildings under real-world conditions. Prototypes of hydrogen-powered heating systems were successfully tested over the course of two heating seasons.
H2Direkt is part of the TransHyDE flagship project, one of three hydrogen flagship projects funded by the Federal Ministry of Research, Technology, and Space. As part of TransHyDE, technologies for the transport and storage of hydrogen are being further developed and tested.
Conversion kits enable H₂ operation
In May, the field-test units from the pilot phase were replaced by Vaillant Germany’s ecoTEC plus VC series condensing boilers — marking the completion of the transition to regular operation. The units are designed to be capable of running on 100 percent hydrogen using conversion kits provided by the heating technology supplier.
The conversion kits consist of gas-flow components and control elements. According to the company, converting the condensing boiler using the kit takes about as long as a normal maintenance service.
Starting in 2027, an electrolyzer is expected to produce hydrogen
Currently, the hydrogen is still being delivered by mobile trailer. Starting in 2027, an electrolyzer will produce theH2 directly on site. Also planned is a hydrogen storage facility and a phased expansion of the network.











