We are in virtually in the same position. From what I have found out so far, you need to make sure that your insert is designed for zero clearance so that it does not generate too much heat for the enclosure. You may have information on the UL rating for your chimney as well (mine is UL127). The insert should be tested to that spec as well so that it does not generate too much heat. I have found three brands so far that may fit Avalon, Regency, and Sierra. You might also consider a Hearth stove. It sits out on your hearth and if you have enough space in your room, you just have to extend your hearth another foot and a half or so in front of your door (local regs).