A study published on July 30 in the Journal of Public Economics by economists Patrick Bigler from the University of Lausanne and Benedikt Janzen from the University of Passau found that the installation of solar panels by a household can influence its neighbors' behavior. The researchers analyzed data from 260,000 households in the canton of Bern, Switzerland, between 2008 and 2019. They combined electricity bills, solar installation records, vehicle registrations, and tax data. For each household and year, they calculated the distance to nearby photovoltaic installations, giving more weight to those closest. The study found that each additional solar panel installation at 100 meters reduces a household's annual electricity consumption by 0.21%, or approximately 11 kWh per year. At 10 meters, the reduction reaches 2.1%. The effect diminishes with distance, down to 0.04% at 500 meters. An installation at 100 meters increases the probability of equipping oneself with solar panels by 2% and the probability of buying an electric car by 2.3%. At 10 meters, these increases rise to 20% and 23%. The researchers suggest the effect is linked to social norms, as seeing solar panels on neighbors' roofs gives the impression of a neighborhood making efforts for the climate and pushes people to follow the trend. The decrease in consumption does not first come from households that install themselves. Households with poorly exposed roofs mainly react by consuming less, since they cannot easily install panels. The effect varies according to profiles, being more pronounced in the countryside than in the city, where anonymity would weaken the influence of neighbors. For the purchase of panels, it mainly concerns homeowners of single-family homes. Tenants, who do not have control over their roof, feel it much less. The decrease in consumption is also much stronger among households whose income exceeds the median. In France, the conditions for solar panel adoption are increasingly favorable. According to data compiled by Hello Watt from Enedis, 6% of single-family homes had solar panels by the end of June 2026, compared to 3.26% three years earlier. However, the rate of new installations is slowing down. According to the same data, 185,030 solar installations were connected in 2025, 26% less than in 2024, and 62,759 in the first half of 2026. These figures cover all connected installations, and not only private homes' roofs. For any connection request submitted since June 5, 2026, the self-consumption premium has disappeared, and the surplus injected into the grid is only bought at 1.1 cents per kWh, compared to more than 10 cents a few months ago. A neighbor connected before this date retains the rate obtained at that time. For a new project, profitability mainly depends on the share of production consumed on-site and the installation of a storage battery, also called a solar battery.