im not an expert on fireplaces.. but i know that the thick heavy metal wood burning stoves ones are really amazing .. they push a lot of heat out.. a stone fireplace or built in isnt nearly as good as most heat goes out the chimney and the stones don't get nearly as hot as metal.. i made a builtin one on in my earthship and it is pretty useless.. u have to sit right next to it to feel much,, and it seems so silly to watch most of the heat fly out the roof!

hope that helps!! <3 x