Sunspots That Matter: The Effect of Weather on Solar Technology Adoption

This paper tests for the presence of behavioral biases in household decisions to adopt solar photovoltaic installations using exogenous variation in weather. I find that residential technology uptake responds to exceptional weather, defined as deviations from the long-term mean, in line with the average time gap between decision-making and completion of the installation. In particular, a one standard deviation increase in sunshine hours during the purchase period leads to an approximate increase of 4.7% in weekly solar PV installations. This effect persists in aggregate data. I consider a range of potential mechanisms and find suggestive evidence for projection bias and salience as key drivers of my results.