Just put your own ductwork in. You're getting a deal so spent a few bucks and some time and do it right. Or just run water lines and use rads. It isn't hard. I bought a used owb, installed the lines, rads, water heaters etc by myself. Yeah, I might burn a more wood than having some expensive ahole design something but don't really care much about that. My paybck is going to be pretty short, well on the own end of things it is. The amount of crap I bought to cut and split wood will never be paid back in my lifetime. And that also ok with me.