How Households Adopt Sustainable Innovations? A Free Decision Enforced by Others

Households play a crucial role in the transition of the energy system. They can make major contributions to sustainable development by adopting “green” innovations since such actions have a substantial impact on overall energy consumption. Theory suggests that innovations are first adopted by persons with specific dispositions, i.e., people with a high level of technical interest, relevant knowledge, and proenvironmental orientation. As an innovation spreads, early adopters yield social influences on others encouraging them to adopt, too. In theory, such effects should be found regardless of the nature of the innovation. We compared three green investments (residential insulation, solar thermal energy systems, and e-cars) at different diffusion stages in Germany. In three experiments, decision-makers in households were asked for their willingness to adopt the innovations; their dispositions and perceived social influences were measured in questionnaires. Social influences were found to affect all innovation adoptions while dispositions showed specific effects: technical interest was found to affect e-car and solar thermal energy adoptions; a proenvironmental value orientation only affected residential insulation. We conclude that it is worthwhile to shape policy measures to the innovation characteristics. However, social influences should always be taken in account.