Study finds that rooftop solar panels are contagious within neighborhoods

  • By Barry Fischer
  • November 8, 2012

A new study, based on 10 years of California data, has found that people whose neighbors have already installed solar panels are more likely to install solar panels themselves.

In a fascinating demonstration of how “peer effects” can strongly influence human behavior, the in-depth statistical study (conducted by economists at Yale and NYU) suggests that for every extra 10 roofs having solar panels within a given zip code, the probability that an additional household will install panels increases by 7.8%.

The authors, whose analysis of 85,046 residential solar installations controlled for other demographic and market factors, explain that the role of neighborhood contagion in boosting the popularity of solar panels likely stems from a couple of behavioral phenomena. For example, they point to word-of-mouth effects (e.g. neighbors spreading the word about how solar energy has decreased their electricity bills) and conformity effects (e.g. neighbors don’t want to be one-upped by their panel-installing neighbors).

One of the most interesting aspects of the study is its implication that the best strategy for marketing solar panels…may be to focus on communities that already have them.

For more about the growing role of solar energy in the US, check out our recent blog post, “Rooftop solar panel installations in US now add up to 4 coal-fired power plants.”

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Outlier explores trends in how people are using energy in the US and around the world. Pulling from an unprecedented (and still growing) amount of energy data—currently drawn from 50 million homes—Opower crunches energy-use information from more than 90 utility partners every day, and cross-references that with weather, household, and demographic information to produce compelling analyses in the Outlier series.