It's important that an indoor fireplace flue damper be opened before igniting anything in a fireplace. The damper looks similar to a trap door and is located at the bottom of the chimney. When it's open, it provides an opening for smoke from the fireplace to escape. If it is closed while a fire is lit, smoke will enter the room rather than leave via the chimney with possible deadly consequences. If nothing is burning in the fireplace, keep the flue damper closed. This saves money on energy by preventing heat or air conditioning loss up through the chimney.