Lynn Jurich is co-founder and CEO of Sunrun, which installs residential solar panels and provides maintenance on them for free. Homeowners then buy their power from Sunrun, which reduces their electric bill by roughly 20 percent. Jurich started the San Francisco business in 2007, with partners including executive chairman Edward Fenster, and took it public last year.

-- As told to Leigh Buchanan

Nature is what drives me. Clean air and a clean environment are human rights. But while that's what excites me, I know I can't build a big, successful company just selling "green." Yes, there's an audience for that. But there's a larger audience that cares more about saving money and equates "sustainable" with "premium."

So it's smart for green businesses to focus on the value angle. You have to explain how customers will save money or get higher quality or performance. For some customer segments--people who don't want to be associated with "tree hugging"--you should probably avoid the green language altogether.

100KThe number of U.S. customers Sunrun has acquired since its founding in 2007

Sustainability is an important macro-trend, but it helps if your business represents other macro-trends as well. For example, Sunrun is part of the decentralization of the energy industry, which is shifting from large plants to power that is generated locally. We also benefit from informed consumers increasingly having the upper hand in buying decisions--and that applies to energy, too, now that solar power companies are taking on the utility monopolies. Why would you buy your power from a company that sees you not as a customer but rather as a "rate payer"?

One of the greatest challenges in our industry is to get our costs down so that we don't need government incentives or subsidies. (And, by the way, all energy is subsidized.) Being public has been a positive experience, because the quarterly march helps us stay focused and hit the numbers. It also gives us more visibility to talk about the financial benefits. Lack of awareness is holding this industry back. There are still too many people saying, oh, solar, that's too expensive. To help counter this, our marketing has been relentlessly focused on savings. We've run a series of TV commercials across our markets featuring a Sunrun customer whose neighbor mocks him for going solar--until the Sunrun customer explains how much he'll save. ("I'm going to be carrying a fat roll of bills, like a rap mogul," he says at one point.) The ads are funny, and they're not subtle. The tagline on those commercials and on all of our other marketing is "Save 20 percent on your electric bill."

To massively affect climate change, you need to have mass customer appeal. It's a big, ambitious goal. A sustainabil­ity message alone won't get you there.