Fireplace doors are decorative metal frames that are attached to your fireplace opening with glass doors attached that open and close. The fireplace door is to be left open while burning a fire and closed when the fireplace is not in use. This is to allow the heat of the fire to enter the room when burning but not let the heat in your house to rise up the chimney when not in use.It is very important to measure your fireplace opening to make sure you get the proper size fireplace doors for your home. You will need to opening height and width and a few other details about your hearth that you can choose during the order process. Fireplace doors come in a variety of shapes, sizes and finishes and sometimes have other options as well.