With permission of all the Experts, may we talk some real world burning ? Please. Indulge this log-winded rant. Over too many years, too many cords cut and used, many many varieties of wood stoves used in some New England homes, here's what has been learned. "Non cat" stoves were, until the renaissance of wood burning in the 70's ( whew, long past ), the only kind of wood stove except for later add-on catalytic combustors that were added to stove pipe. The real Vermont Castings ( look up their engineering history - Defiant and Vigilant) ) designed a form of "reburning" gases through convoluted smoke paths. Some Scandinavian stove makers such as Lange, Morso, Jotul, had other designs to re-burn such as a "loop" before exiting ( see Morso 2BO for example). Later stoves were engineered for built-in cats such as VC and Jotul's Firelight. So here's the skinny: IT"S THE AIR ! So, cat stoves allow the primary air ( some have also thermostatic secondary also) to be near closed completely. This allows the smoke to be burnt by the platinum/paladium coating on cats. Therefore, cat stoves will and can be controlled for longer, more efficient burns. Now non-cats ( NOT hybrids) regulate the primary air so it's not too high, not too low to control emissions and heat--TO A DEGREE ( pun intended). Its a mommie stove. Look over The Bungalow Effect explanation- john G. does an excellent job here. Now for the real world. We use a cat (VC Encore 2550 circa 2001) for one part of the house. Another same sized part heats with a Jotul Oslo. Both stoves run 24/7, 99 44/100% of the time with no central backup or furnace; just a small propane space heater for one part when on winter climbs or away to keep the pipes from freezing. Fact that over the 8 years with both stoves, the Oslo will use ~ 1/4 to ~ 1/2 MORE wood ( same species and seasoning ) than the cat Encore. The Encore will hold heat and coals ( like the BK line) close to twice as long as the non-cat Oslo. We will burn 6-8 cords of Red/Soft Maple, Paper/White Birch, and some White Ash, Red Oak, Apple saved for those single and below zero days. Addendum: an ancient Tempwood heats a workshop, and a Snorkel Hot Tub wood stove both use softwood blowdowns ( spruce, fir, cedar). Used a "thermostatic controlled" Ashley long ago in ignorance of its wondrous creosote production. I am dismissed, and tired of winter. Next year's firewood is piled in butts ready for the round of split and stack. Oh yes, we long ago ceased trying to keep the clear ceramic on the stoves clean. No time.