No cupola, but I do have a ventilation fan right above the evaporator. It's hard to see in the photo, but the floor in the building is split level, and correspondingly so is the roof. The fan blows through the short "end" wall onto the lower section of roof. It works, but it just can't keep up. These things make a lot of steam.
Dave, there's no freezing fog inside the building..
It's not like a wood fire in the stove, this thing is wide open all the time. No damper in the pipe, and the draft control cranked open. The flames start at one end of the barrel, and are pulled all the way to the stovepipe on the other end, a distance of about five feet.
It roars pretty good, and keeps me toasty.
