I have noticed with the woodstove... like any good stove, it really doesn't kick into gear and perform till the feed air is cut back and the flue mostly blocked off. Once that is done, the fire kicks into hyperdrive and it begins cranking out some serious heat. Till then, it's just coasting along and playing... and not getting 100% from the fuel. Give the stove more air than it can use, and it will waste fuel and put out less than half the heat it could if well managed.
I wonder if the analogy* holds true with people?
*'Analogy'.... that's like when you compare one thing to another.