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.
Wood offers a renewable and sovereign source of energy. Wood fuel is available in plenty and there are lower chances you can lack ready wood fuel for sale. As for oil and gas, they are non-renewable so you can expect them to run out any time without prior warning. As for electricity, it is produced by burning fossil fuels which a limited commodity meaning it can run out any fine day.