In this part of the country fireplaces are basically for entertainment.  Truth be known, they actually consume more energy than they produce.  The modern day inserts are more functional than their predecessors but are still basically something to look at on a rainy, cold day.   Some freestanding wood burning stoves are engineered to produce enough energy to heat a small home but and not common in most of our homes. 

Older masonry fireplaces consists of; a footing, firebox with a front and rear hearth, a damper, throat, smoke shelf, smoke chamber, a mantle, a chimney with its components, and in some cases a ashpit for easy cleanout.

Factory built boxes and insert do not have hearths, although a front hearth must be provided, and do not have smoke shelves or chambers.  The damper connects directly to the chimney vent and must have a damper stop, so that with a combustible unit, it cannot be completely closed.

Perhaps the biggest issue with today’s fireplaces is clearance from combustible and proper firestopping.  Scientific data are available to explain the issue of wood coming in contact with surfaces that exceed 250 degrees F. and that this charred wood can actually start a fire over time. These combustible issues are normally inspected during the framing stage of construction.  Proper firestopping is simply not allowing an open chase, around an insert box, access to an attic.   As the chimney vent passes through the attic subfloor it must be clear of combustibles and the remaining open area must be properly firestopped with a material that provides at least one hour of fire protection.  In the case of a metal chimney this is almost always a flat tin cap or insert.

One other issue.  With wood burning fireplaces it is always a good idea to have smoke and carbon monoxide detectors as part of your homes safety devices.