California has caught a serious case of solar power. A new study by Yale analyzed “Peer Effects in the Diffusion of Solar Photovoltaic Panels” and the conclusion was that solar power is contagious. Solar installations in the San Francisco Bay region over a 5 year period were studied and were found to have spread similar to a contagion, as pictured in the year comparison chart below:

And, through some fancy equations, they were able to ascertain “evidence of a causal peer effect in which a one percent increase in the zip code installed base leads to just over a one percent increase in the adoption rate.”

It seems that installing solar power is like anything else – few people want to be first. They would rather see someone else they trust go through the process before they’ll experience that peer pressure to look into it too.

If you have a solar power system installed, perhaps that’s been your experience. Neighbors, friends, and family are curious about the savings and want to know if you like your system and if you recommend the company you used. They have tons of questions and want to see if solar will work for them.

Another thing the study revealed was the major reasons most people install solar power (Fig 11-3 below) on their home. For the most part, the choice to go solar is for financial reasons, with concern for the environment a close second.

For a comprehensive breakdown of the study findings, take a peek at this great article over on ThinkProgress.org.