Fireplace Cobra home heat adaptor

It has been chilly here at BUNGCO headquarters. But it is painful watching our valuable therms disappear up the fireplace! Is there not some way to make our fireplaces heat rooms better without spending exorbitant amounts for retrofits, and also minimizing the risk of a ruddycheeked mass death from CO poisoning?

BUNGCO is aware that fireplace inserts exist. They are lame (link). There is no mass to heat and the air intake and outflow are essentially next to each other. Bah.

The Fireplace Cobra is made of heavy cast iron, weighing 75 lbs. The tail is blue and is intended to hang out of the fireplace and project laterally. It is the air intake. The tip is fitted with threads and one can attach a garden hose for air intake from more remote sites - like outside. Inside the fireplace the Cobra is comprised of a square pyramid of coils, using straight pipes and elbow turns. The head, or the top is red and is meant to project out the front of the fireplace.

The Cobra is heated from below with gas jets (if placed on the log rack) or burnt wood (in which case leave the chimney open). As the pipes heat up, cold air will be drawn in the tail, traverse the pipe and then blow out the head into the room. Once it is hot, the heated mass of the Cobra will continue to heat air long after the source of heat is turned off or goes out.

With a longer head attachment, the Cobra can be set atop a gas or charcoal grill outside, with hot air coming thru the head pipe into the dwelling, thus heating it without risk of carbon monoxide poisoning.