We have never used our fireplace since we bought this house in 1984 because we thought it needed a liner. It was built in the early 1930's. We recently had a mason come out mainly because some bricks fell off the top of the second chimney for the furnace. He said we could have fire in the fireplace as is and did not need to add a liner. But what if we put a wood or hopefully multi wood, coal and pellet burning (if there is such a thing) insert into it? Do they burn hotter and produce more creosote and thus need a liner. Searching briefly for inserts I saw that some come with a steel inner chimney pipe. Are those required? Does it need to go all the way to the top of the chimney?