Gregory,
I have looked at these before. I think what they mean by “ductless” is that it can be configured in such a way that the exhaust comes out the upper back of the stove instead of the top. The main advantage is that in the “ductless” configuration, the top provides a modest area for cooking or warming up
coffee, etc. In the ducted very, there is precious little area on top for anything useful.
As I remember, these stoves were pretty good at warming up a small to medium sized space. The downside is that they do not burn for very long and need refueling every 30-60 minutes.
I wonder how much wood a person would need to keep one of these going. Also, the wood needs to be cut up to something like 6” pieces to effectively fit in the stove. It might be a lot of work cutting and
splitting wood to heat for a short time, but maybe in some situations it could be useful. I would be curious to know if one of these might augment a RMH by helping to warm a space quickly while the mass of the RMH heats up and starts to radiate.
At any rate, these are just a few thoughts and memories I have of these little stoves.
Eric