There are plenty of logical reasons to get solar panels on your home, including saving money in the long term, reducing your carbon footprint, and helping homes break free from the electric grid. But one of the biggest motivating factors? Whether your friends and neighbors are doing it.
In the residential solar market, research has shown that peer pressure is a strong factor in purchasing decisions. One 2014 study, by Yale University and University of Connecticut researchers, mapped almost 4,000 solar units over a decade and found "considerable clustering of adoptions" in "wave-like centrifugal" patterns. They found that one installation within a group of households increases the chances of a second installation by almost 50%.
New data from the solar installer SolarCity shows this phenomenon in detail. The company looked at its referral program and found the 10 cities with more than 100 installations where the largest percentage of installations came from referrals—all were above 50%. Six states are represented on the list.
You can see what solar "contagiousness" looks like in Honolulu:
And in Fort Collins and Greeley, Colorado:
As solar panels become more popular—2015 saw the most installations in any year by far—they will continue to spread as people see their neighbors have them. I noticed this myself when I visited by parents’ house on Long Island after a few months away, and all of the sudden out of nowhere, about a quarter of my immediate neighborhood seemed to have installed rooftop panels. This is a good kind of keeping up with the Joneses.