As companies like SolarCity and Sunrun look to expand their residential solar empires, here's an insight to aid their marketing efforts: People are more likely to get solar installations when their neighbors already have them.
Peer pressure is known to heavily influence our buying decisions, and it turns out to be a particularly strong factor in home energy purchases—stronger, in fact, than other factors, including politics or income.
Researchers at Yale and the University of Connecticut mapped 3,843 solar units installed in Connecticut between 2005 and September last year and found "considerable clustering of adoptions" in "wave-like centrifugal" patterns. When they looked at the dates of the installs, they found one decision in a neighborhood tended to lead to another.
Kenneth Gillingham and Marcello Graziano say the installation of one PV system in the previous six months within a 0.5 mile radius "increases the number of installations in a block group by 0.44 PV systems per quarter on average." That is, one installation within a group of households increases the chances of a second installation by almost half.
Gillingham told the Washington Post that peer effects were more important than the income or politics of the home-owner. You might think someone richer and more liberal would be more likely to get a PV system. In fact, the biggest clusters were in middle income, Republican-voting areas of the state, according to the analysis.
Which proves two things perhaps. One, it's a bad idea to stereotype renewable energy adoption. And, two, you shouldn't discount the power of a peer group.