Buildings have a great potential to produce their own electricity thanks to affordable photovoltaics and available area roofs and facades. To be self‐sufficient over the year, the electricity converted to hydrogen by electrolysis during the sunny season can be re‐used with the help of fuel cells during the winter season. Self‐sufficiency of the building as well as a drastic carbon emission reduction can be obtained thanks to the introduction of PV systems coupled with Hydrogen seasonal storage. For Solar Hydrogen project, a schematic design phase is mandatory : dimensioning of the PV and storage systems, suggestion of reliable technologies available on the market, needed infrastructures and security. In this article, we introduce the case study of the first private building that will be equipped with solar hydrogen storage in western Switzerland. Dimensioning is performed with the help of the Polysun Simulation software and specific add‐in modules in python.