Gary: a lot of chimneys won't draw well enough to keep a fire going at extremely low settings like you are using. You are lucky to have such a good drawing chimney.
Barley. I'm certainly not advocating changing the firebox size everytime the weather changes for a day or two. But if a person's stove is just too big for the application, then why burn extra coal when [if] it is possible to reduce the firebox size to better fit the application??
I do everything I can to minimize the quantity of coal I burn. Because I'm a 10 hour drive one way to the breakers. Or I can pay $300+ a ton in my state. Nope, not me, unless I'm desparate. I can't take two days off work to do a jaunt to Pennsylvania after coal.
So I reduced my firebox to burn an optimal amount of coal. If the trend is for it to be cold, I can easily increase the box size without letting the fire go completely out.
I'm certainly not going to open windows and warm up the neighborhood. That defeats the purpose of burning coal in the first place. If I had money to burn, I'd just crank up the thermostat and pay $1200-$1500 a month for propane.
I agree that for short term warm temperatures just opening the windows is a method to keep the house from being uncomfortable. But if I wanted to heat my place during two or three weeks of 50*days/35* nights with a hand fired stove, I'd size the firebox to fit the heat requirements, not burn excess coal and open windows. I'm too frugal [read cheap
This is mostly a moot point anymore, the temperatures in Michigan are trending towards 'normal' 20's in the day, teens at night. Forcast for 12* Monday night.