Though neighborhood opposition is often cited as an obstacle to greater adoption of urban rooftop solar, it turns out that neighborhoods might offer positive pressure for homeowners to install solar as well. A study published in the most recent issue of Marketing Science found that every rooftop solar installation in a California ZIP code made it more likely that neighbors would install solar on their own roofs, too.
The study's authors, Bryan Bollinger of NYU's Stern School of Business and Yale School of Forestry & Environmental Studies's Kenneth Gillingham, studied the levels of rooftop solar "penetration" in California ZIP Codes from 2001-2010. They found that each 10 additional rooftop solar installations in a ZIP Code made it 7.8% more likely that another homeowner in that ZIP Code would install solar on her own roof.
ZIP Codes with 10% more rooftop solar at the outset of the study gained around 54% more new installations.
"If my neighbor installs a solar panel and tells me he's saving money and he's really excited about it, it's likely I'll go ahead and do the same thing," Kenneth Gillingham told phys.org. "Then there are others who'll install because they don't want to be one-upped by their neighbors."
Bollinger and Gillingham say they were able to correct for possible confounding factors such as local environmental attitudes and political views. Even correcting for some neighborhoods being green hotbeds and others being environmentally unsympathetic, peer pressure seems to work to encourage others to install rooftop solar, with -- ReWire would guess -- potential for exponential effects once a critical threshold is reached. Assuming the state's current relatively meager homeowner incentives don't wither away altogether, that is.