It may sound like a flaky idea, but corn is heating thousands of homes in Wisconsin. The same kernels that go into ethanol and animal feeds can also go into a fireplace or furnace, to either completely heat a home, or as a supplemental heat source, according to George Penn with Global Energy Options in Madison. Wisconsin's Focus on Energy program estimates that there are about 8,000 corn stoves in Wisconsin. There's a "green" element here: Penn says corn does burn cleaner than most other home heating fuels. How about cost? Penn says if corn gets below three dollars a bushel, it can be competitive against other fuels, especially L-P and oil. Lots of the corn stoves and furnaces in Wisconsin are located on farms, while other owners have arrangements with farmers in their areas.