While the environmental benefits of installing photovoltaic systems are clear, the costs can remain off-putting for private households. In this video, SVEN MÜLLER explores the relevance of the peer effect (neighbors already having the technology) in a decision to install a photovoltaic system. Establishing an installed base and considering fixed effects alongside an instrumental variable approach, Müller finds that peer effects are most prominent on a very local level i.e. within a distance of 100m. He also shows that the visibility of an existing photovoltaic system plays a vital role in its potential influence in the neighborhood. Further research will examine if this phenomenon is also observable outside of Germany and to what extent it is relevant to other new technologies (like electric vehicles).