[RobertSmalls]

Most (okay, all) of the fireplaces I've seen draw in combustion air from the house, and send most of the energy from the wood up the flue. These are primarily decorative devices.

You could get good efficiency from a wood-burning device that draws combustion air from the outside and has heat exchangers on the flue, plus a good seal on the flue cap. But I don't see any efficiency advantage of a fireplace over a wood-burning stove.