Solar Panels Could Be the Best Fad Ever

“Oh, you should totally do it,” my neighbor said.

I was nursing a beer at his winter holiday party as he told me about the solar panels on his Brooklyn brownstone roof. They’d cut his electricity bill down so much that in a few years they’ll have paid for themselves, he told me. I had questions: Did it damage his roof? Were there any complications? Any regrets? Nope: If anything, he wished he’d put up a bigger array, to produce even more juice. “It’s great,” he gushed.

I went home, intrigued. I’d been thinking about putting an array on my roof for years, but something about my friend’s confidence pushed me over the edge. I called up Brooklyn Solarworks, a local firm, and their crew of electricians arrived and, with a chill, we-got-this vibe, installed a gorgeous, sleek set of panels. It’s a “canopy” setup, with the panels raised 9 feet above my roof on thick, shiny aluminum braces, crafted with such perfect welds it made my engineering-nerd heart swoon. My house is old, built in 1902, so the canopy lends it a vaguely William Gibsonian aesthetic: a ramshackle blend of vinyl siding, snaky wiring, and dark promise. You can see the panels from a block away; they attract attention.

Indeed, a few months after they were installed, I got a knock on my door. It was a neighbor from around the corner who’d seen my solar array and, like me before him, was intrigued. We clambered up on my roof, and I told him how they’d cut my electricity bill by about 80 percent, and frankly I was happy as a clam. With the tax credits I got, the panels would pay for themselves in seven years, after which it would be—well, crazy-cheap electricity for life.

My neighbor walked back home. And a few months later, a solar canopy popped up on his roof too.

Solar, it turns out, is a virus—a good one. Researchers have been documenting this, and it offers some intriguing hope for climate-change mitigation. Now that we know solar uptake has a social spread, we may be able to make it spread faster.

In a 2014 study, Yale economist Kenneth Gillingham and a colleague looked at the adoption of residential solar installations in Connecticut and found that it spread through neighborhoods in a “wave-like centrifugal pattern.” A subsequent study, by economist Stefano Carattini, then at Yale, and two colleagues, documented the same phenomenon in Switzerland. And when I dropped by the offices of Brooklyn Solarworks, the folks there showed me a map of where they’d installed panels. Sure enough, it was all epidemiological hot spots—you see empty streets with no solar at all, then blocks that are simply crammed with it, neighbors next to neighbors with arrays.

This makes sense, right? We’re social animals. Whether it’s fashion or jokes or political views, we take cues from those around us. Social influence is particularly useful, though, when a life decision is expensive. Solar may save you money in the long run, but up front it’s the price of a car, which can give one pause. “There’s some uncertainty. You don’t know exactly how things are going to play out,” Carattini tells me. So we gain confidence when someone near us takes the plunge. It also helps when they’re similar to us. Carattini found that when farms put up solar arrays, it spreads to other farms, and the same thing happens with corporations. Like attracts like.

Plus, putting up panels is peacocking that’s easy to spot. “It’s actually visible on your house, and it’s always visible,” notes Evelyn Huang, the chief customer experience officer for Sunrun, a national solar firm. She cited market research showing that the majority of people who installed solar believed that a quarter of their community had already done so. That’s probably a false belief—I doubt rates are that high anywhere in the US. But it’s a usefully beneficent one. People build a mental model of the awesome behavior they think is going on around them and join in.