CHICAGO – A few years ago, Jim Camasto thought about investing $20,000 in the stock market.

But instead, Camasto, 43, of Naperville, Ill., spent that money on a “greener” investment — solar power.

Camasto has installed a solar thermal and solar electricity system on his roof, which helps heat and power his home.

His gas use has dropped more than 50 percent, and his electricity use has dropped about 70 percent. He sells extra power back to the electricity grid and sells renewable energy credits, which investors buy and trade to support renewable energy projects.

His return on his investment is about 3 percent or 4 percent a year.

“Some people say that’s a slow return,” he said. “But I’m willing to bet utility costs are not going down in the next 10 or 15 years. There’s very little risk. I’m glad I made the investment.”

Although the price of solar panels is falling, the upfront costs of installing a solar power system can still be daunting. But many states have incentives designed to help finance renewable-energy projects. And there are federal tax credits for up to 30 percent of costs available to homeowners and businesses that buy solar or wind energy systems.

Mark Burger, president of the Illinois Solar Energy Association, said installing solar power is like making a major home improvement, with the cost being roughly equal to adding a new bathroom or remodeling a kitchen.

It’s a buyer’s market, Burger said, and a solar-powered house that promises reduced utility bills for years can be a major selling point.

“Developers are realizing that putting solar on homes to make them more ‘green’ is the only way to save the real estate market,” Burger said.