A fireplace glass door is installed on a fireplace to keep the room warm longer when the flames die down. Whether a wood burning fireplace or a gas burning fireplace, heat radiated into the room escapes through the chimney. One does not notice this while the fire is burning brightly, because of the heat from the flames that radiates into the room. However, when the fire starts to die down, the hearth becomes cold quickly as the heat escapes through the fireplace opening. To stop this from happening, a fireplace glass doors blocks the opening, keeping the warm air from leaving the room.
A corner fireplace door is somewhat smaller than an ordinary fireplace door. They usually come in the traditional accordion-type frame because of the limited space offered by the walls. In choosing a fireplace door from the rack, the purchaser has to ensure that the door is big enough to cover the widest area of the fireplace opening without covering the whole mantle design. The door should overlap the whole fireplace opening in order to serve its purpose, but should not keep the fireplace itself from being seen and admired.