Remember, before using a fireplace, have it inspected. The inspector will look to see if the chimney meets current building codes.
Chimney liners reduce the heat transfer, which can limit fire hazards from exiting. Transfer of heat can be caused by support structures or combustible framing near the chimney, which can ignite if the heat from the chimney transfers over to them.
In older homes, inspectors frequently find chimneys that are too short or without liners. If there is a liner, they’ll inspect it for cracks that could allow heat to escape.