From what I understand, modern fireplaces and wood stoves can be 70% to 80% efficient. Rocket mass stove can be over 90% efficient. I don't know how efficient pellet stoves can be. Smoke is from the wood that isn't completely burned, so more efficiency means more combustion and less smoke. My guess is that this is also going to be a lot better for health than an older and less efficient wood heat source. I would be interested in knowing how accurate I am but a quick web search hasn't turned up a whole lot.