In the Energy Strategy 2050, approved at the ballot in May 2015, Switzerland has defined ambitious goals, which include a transition of the energy system from fossil/nuclear towards renewable energies. However, the implementation of respective infrastructure projects has proven to be difficult and slow, not least due to political opposition and actors’ reluctance to invest in according projects. These challenges have been intensively discussed in the research on social acceptance of renewable energy infrastructure, where infrastructure for renewable energy production has been the focus of many studies. Seasonal or long-term thermal energy storages are another central element of the energy transition, which – as we will elaborate below – are similarly affected by acceptance and related diffusion problems but have so far received much less public as well as scientific attention. This is the starting point of the SNF project SOTES, in which we ask the overarching research question of how to achieve a breakthrough of long-term thermal energy storage in the residential sector in Switzerland.