A fireplace is a masonry structure that encloses some form of fire box, with damper and venting, that attaches to a chimney. There are two basic types of fireplaces: Heatilator and Zero Clearance.

Heatilator fireplaces contain a double-walled steel fire box (complete with venting, damper and chimney attachment), called a heatilator, completely enclosed in masonry. The heatilator has an air chamber surrounding the firebox which draws cold air into two bottom vents, heats it, and by a process of natural convection sends this hot air out two top vents. A fireplace with a heatilator is vastly more efficient at producing heat than conventional fireplaces including 'rumfords'. If properly installed with glass doors and an outside air source they are about 75% as efficient as a wood stove.