How To Make A Passive Fireplace Heat Exchanger
Most states now ban the old-fashioned style of hearth fireplace in new construction and remodeling because it sends more heat up the chimney than into the room. One way to partially reverse that heat loss is with a fireplace heat exchanger.
This utilitarian appliance works simply by drawing cold air from the floor level into pipes, heating the air, and expelling the rising hot air from the fire back into room. click the link below to see how you can build one your self.