Modified Fireplaces
A modified fireplace consists of a heavy metal manufactured unit designed to be set in place and concealed by brickwork or other masonry construction (see Figures 3-13, 3-14, and 3-15).
Modified fireplaces are usually more efficient than the all- masonry type because provisions are made for circulating the heated air. As shown in Figure 3-16, cool air enters the inlets at the bottom and is heated when it comes into contact with the hot surface of the metal shell. The heated air then rises by natural circulation and is discharged through the outlets at the top. These warm-air outlets may be located in the wall of the room containing the fireplace, in the wall of an adjacent room, or in a room on the second floor. Sometimes a fan is installed in the duct system to improve the circulation.
