In a home, is there a minimum distance required from the electrical panel to a fireplace or furnace?

We're looking at a home in Indiana, and the electrical panel is right behind the furnace. The wall it is mounted in is also the wall that is right behind the fireplace. Is there code now saying this is unacceptable? There was another couple looking at the house and they said that it would have to be moved. I'm not sure if they were right, or just trying to throw us off.