Kevin and Stacey Rademacher’s house in Sherman looks a lot like their neighbors’ houses, except for one thing: the large, black solar panels covering the Rademachers’ roof. Kevin Rademacher says he installed the panels himself in May 2013, after purchasing a Chevy Volt, a hybrid car. The solar panels provide about half of the Rademachers’ electricity and about 85 percent of the Volt’s battery power, which works out to about 10,000 miles of driving. Rademacher says his net investment was between $10,000 and $11,000 after state and federal tax incentives and rebates from his power company. The system generates about $900 of electricity annually, he says, meaning it will pay for itself within about 11 years. “The return on your investment is really pretty good,” Rademacher said. “It’s almost guaranteed because you’re going to need electricity, and the price of electricity typically goes up, not down.” On Saturday, Oct. 4, 10 a.m.-2 p.m., the Rademachers will open their house as part of the 2014 Illinois Solar Tour, a statewide expo of more than 60 businesses and residences that use solar power. Six other Springfield-area sites are featured on the tour, including Southwind Park and the home of Bob Croteau, energy planner for Springfield City Water, Light and Power. For more information, visit www.illinoissolartour.org.