In the past, iron stoves, fed by wood, charcoal, or coal, were also used for cooking. They had an oven below and pot holes on top. However, because they gave off a large amount of heat, they made the kitchen an uncomfortable place in the summer. Today, iron cooking stoves have been replaced throughout most of the industrialized world by gas or electrically heated cooking ranges and ovens. The modern fireplace has a carefully proportioned opening set into a wall, a chimney, a device called a damper to regulate the draft, and a smoke shelf to prevent downdraft at the entry into the chimney.
Heat is radiated into the room by the glowing fire.
However, since inside air must be continually drawn into the fireplace to keep the fire burning, the rest of the house may actually be cooled down. This can be avoided by flanking the sides of the fireplace with special ducts. Cooler room air enters these ducts at the bottom of the fireplace, is heated by contact with the hot fireplace walls, and then is discharged back into the room near the top of the fireplace. Other fireplaces draw air from outdoors to keep interior air from being drawn out through the chimney. With the advent of central heating in the 19th century, the use of stoves and fireplaces for heating began to decline.