A common design is a metal circulating fireplace enclosed with brick that forms a structure around the fireplace opening. Old House Web recommends a fireplace depth about two-thirds the height of the opening. A correct-size flue -- which channels the exhaust from the fireplace to the outside -- also proves crucial.
Steel angle iron supports the masonry above the fireplace opening. Using a heat-resistant material such as firebrick for the interior of the hearth reduces the risk of a house fire. The outer hearth should stretch at least 16 inches from the fireplace front, and use a reinforced concrete slab for support.
Conventional fireplace construction allows about 90 percent of the heat from burning wood to escape through the chimney, reports HandyAmerican.com. An airtight fireplace insert such as a wood stove captures more heat. Airtight stove features include a faceplate and a blower for room heat circulation.