Finally got around to adding an exhaust fan above the loft in my man cave (aka the shed). Works well with adjustable fan speed. I will have to see how much of the heat it sucks out along with the smoke come winter.
I use a radiator space heater that I leave running. It can easily keep it 75-85 degrees depending how cold it is outside. My wife jokes that she has to come outside to warm up as we keep our house pretty chilly.