Bundling Residential Rooftop Photovoltaics with Energy Efficiency Upgrades: Does It Really Pay Off?

Using data from a survey of solar adopters in the USA, the present paper examines the effect of adding insulation on electricity bill savings. We identify whether solar adopters added insulation to their house close to the time of rooftop photovoltaics (PV) installation as a bundling strategy, and examine whether such decisions are correlated with higher electricity bill savings. We find that only 7% of solar adopters in the sample ended up bundling their PV installation with additional insulation. About 58% of solar adopters in the sample have not added insulation at all. The evidence in the present study suggests that solar adopters who choose the bundling strategy have larger, older houses, located in counties with higher electricity prices than those adopters who did not add insulation at all. Results show that while all solar adopters who choose the bundling strategy have a higher average dollar amount of savings, only those with high initial bills end up with a higher percentage of savings. The results of the present study provide some insights into the energy decision-making of households and provide some input for policies focused on combining renewable energy with efficiency standards.