Stack Effect Equation Q= CA> 2gh/ Ti-To = 2x#> 1 the power of 2
Grrr, wheres Larry when ya need him
Berlin is right in that the chimney would naturally be warmer inside then outside therby allowing for a better initial draft (maybe you dont need to ball up a piece of paper to burn in the flu or hold a piece up the chimney in the fireplace before lighting the fire) but after the fire is going and the flu is hot the diff. is pretty pointless.
Lightning also confims that old time theory that the first floor drafts better is indeed because of factors lightning mentions " low pressure in the basement which cannibalizes draft strength"