I have exactly the same stove, almost the same square footage house, and approx. the same chimney.
Last winter (2012), burning 2-year CSS cherry and hickory, I could hold 500 stovetop with my eyes shut, and keep it for 4-5 hours. Temp measured with a magnetic therm at center of stovetop step. Oh, and using pretty big splits- 5-6" on top of coals.
This past winter, I got the same as I finished off that supply of wood, but then got progressively worse results as I started working my way into less-and-less seasoned stacks. By February, I was burning cherry that has sat in rounds for 2 years, but had only been split for maybe 6 months- winter just would not quit and it was that or break up the furniture.
By the end of February, my not-quite-seasoned cherry would only offer an hour or two of flames, and maybe another hour or two of coals, then nada. I stretched it out by adding Envi-blocks, but that's another thread.
Solely based on this, my $0.02 is that there's something we all don't know about the wood. Michael6268, have we checked more splits with the MM? From 4-6 diff places in the stack? And on fresh-split faces? (I know, that's first-grade-level input, but we'll start there...)
