The use of photovoltaic (PV) systems on residential buildings is a key element in the societal transition to renewable energies. However, despite economic and ecological benefits, many homeowners struggle to adopt PV due to technical complexity, administrative burden, and cognitive biases such as inertia. There is also a lack of research on this issue and on how interventions informed by behavioral science could help increase adoption. We address this gap in the literature by conducting a preregistered field experiment involving 600 homeowners in Switzerland, testing whether two types of personalized behavioral interventions, one based on prosocial motives and one focusing on self-interest, lead to tangible actions towards PV adoption. The results from our pilot study show that both interventions substantially increase adoption behavior compared to a control group and a group that received only general information on PV. The intervention focusing on self-interest, which highlighted homeowners' missed revenues in the past year and thereby invoked loss aversion, yielded the largest effect. In summary, our study contributes to a better understanding of how public organizations can use behavioral interventions to promote renewables without large subsidies.