chimney question

First of all, your habit of regular cleaning is to be commended. But if you did go with a liner, if you were to insulate that liner, say by filling the space between the liner and the masonry with pumice, you would keep your gasses a little hotter and might get less creosote. Also a round liner might be a tad easier to keep clean. But a smoldering smoke dragon is a smoldering smoke dragon, no matter what flue you have, and you'll still have to clean just as regularly. (You may get less product when you clean.) JMHO.

Yeah, like Mono, I agree you'll still need regular cleaning. You might be able to reduce your creosote by a percentage, but overall I think your cleaning routine would be about the same.

Also, is the 7" an inside measurement? I know when I lined my 8x12 clay lined flue the biggest stainless flex liner I could fit in there was 5.5" uninsulated. I dont think going with a smaller flue is really a good idea anyway unless specifically permitted by manufacturers manual, or your trying to do something about having too much draft.

You definately want an insulated liner. Draws WAAAY better than a masonry chimney, and also it stays hot and doesn't allow the creasote to form as easily as a masonry chimney would. Plus it's just an all around safer set-up. Think about it, if your masonry liner would crack, you could have big problems. With an insulated liner, that almost totally puts that worry to bed.

Scotty, I agree insulated is always better, I think the problem is space. I dont think you can fit an insulated liner down a 7" masonry can you? I suppose you could do the flex liner and backfill with that perlite or whatever it is stuff. I could probably benefit from that but it seems like a big mess to me, plus it would take a lot since mine extends another whole floor down to the basement cleanout.

As for your other question... new stoves should indicate maximum and minimum flue sizes in the documentation. While not ideal, I'd wager to say 7" (square?) would fall into the rating of most 6" stoves. I am sure you could try it that way to see, and then debate installing a liner if you have draft problems. I was even going to try venting my 6" new stove into our 8x12 masonry just because I didnt have money at the time for a liner. But then I found some online chimney places that were literally half the cost or less than my cheapest local place, and I did the install myself. So the liner became feasible and I went ahead and did the liner. Interior chimney so insulation isnt as critical, and I also sealed the basement cleanout and the raincap to try and stop any cold air infiltration. Just cleaned it out once at the end of the burning season and even though it did have about double of our other stove, the amount wasnt anything to worry about, and the stove drafts fine. YMMV.