Getting a new forced-air furnace for your house? Here's what to do before they haul the old one away. From deep within the Carey Brothers' vault of great ideas for reuse and recycling, we bring news for you that's exciting. Indeed, says here forced-air furnaces have great squirrel-cage-type fans designed to move lots of air quietly and efficiently. Yet when homeowners replace their furnace, few think to ask the installer to remove the fan and leave it behind for other application -- such as ventilation in an attic or crawlspace or as an exhaust fan in the garage or workshop. You're not replacing your furnace just yet? Even if replacement is many years away, you can still benefit today. Heating contractors usually have used fans around. With a few calls a cheap one can be found. And that's the On The House tip for today.