When Brennan Mulcahy created American Solar Direct in 2009 to sell solar panel installations to California homeowners, he eschewed modern advertising and social media blitzes and chose a strictly old-fashioned approach--going door-to-door.

Mulcahy is convinced that no one wants to make a $30,000 investment online or on the phone. So rather than pay hourly wages to high-pressure pitchers, he brought on articulate, educated, environmentally conscious people to work on commission.

He gives them one month of classroom training to start, and then expects them to shadow more experienced salespeople, learn about the solar industry, and visit the distribution centers and job sites. Only then do they strike out on their own. It's a strategy that helped the company grow to $52.1 million in sales in 2013. Mulcahy got people to open their doors--and their wallets--using three tactics.

1. Find the right hook

When Mulcahy started American Solar Direct, he tried to sell his product by focusing on the environmental benefits of solar power that got him and his team passionate about this clean, renewable energy source. But the pitch fell flat. His potential customers cared less about the environment than about their finances. So he shifted the focus to cost savings. And, rather than wealthy homeowners, he targeted the middle class. "If you can save them money on their utility bill every month, its a big deal," he says.

2. Keep it local

The company does no advertising, but relies instead on salespeople ringing the doorbells of middle-class homes near each of its three equipment-distribution centers, all located in densely populated areas. That saves driving time and speeds up installations. The centers are staffed with people who know each community's permitting processes and standards, which allows them to "take a customer from sale to installation in three months, instead of the eight or nine months" typical of other companies, Mulcahy says.

3. Teach, don't sell

Rather than train his team to rely on the hard sell, Mulcahy has them educate potential customers so that solar can sell itself. First, a sales consultant contacts a homeowner to ask permission to assess his or her home and roof configuration using Google Earth. After that data has been analyzed, the consultant returns to show how much money the owner might save. The close rate is about 50 percent of those who get the assessment, says Mulcahy. "There's something to be said for sitting at someone's kitchen table and having a conversation."