About 18 months ago I managed to score about a half cord of paper bark birch. Got into that stuff yesterday,put 4 nice-sized chunks into my firebox and 5 hours later still getting nice heat. Now, out here on the "wet" oops west coast our supply is predomintley softwood,fir hemlock alder and cedar. I burn mostly douglas fir. Anyway,loading the same amount of fir only gives me heat for about 3 1\2 hours . I would be willing to bet that most of the (burn times) that the manufacturers conduct on their stoves and inserts are done with hardwood? Sure wish we had more of that nice stuff in this part of world. Oh, well, at least it doesn`t get cold out here on the coast. :coolsmile: