What is the most efficient type of fireplace?

• Pellet stoves are very efficient and the pellets burn evenly and are comparatively cheap. by DIYpro

• The one that has a wood stove insert installed, instead. No unaltered fireplace is efficient, they allow too much air to flow up the chimney. by Don

• for a standard woodburning masonry fireplace , a rumsford firebox is the most effecient... by Dan the brick man