The unvented is always a big concern -- use only while attended and as little as possible Definitely install a few CO detectors in the house to cover all the combustion you will have going on. The chimney should work.....main thing with furnaces is not to fire them up until it gets nice and cold...then you won't be smoldering. If and when you install ducts for the wood furnace, note that these ducts should not touch wood or combustibles as wood furnaces can get them a lot hotter than others....your manual should have specs on that. If there is none, use 6" from the top of the plenum on the furnace and 2" from the ducts that come out from there - you can probably then go to regular regular boots (which touch combustibles) as long as you are 12 feet or more away from plenum - note that these are guesses based on manuals I have seen. If your manual does not address, download some similar manuals for other wood furnaces and specs should be similar as to duct clearances.