Evening starts at 46 and slides to mid to high 30's for a few hours. Burning hardwood the house gets hot to the point of stuffy yet without it oil heat kicks and drones away for too long for me. I have tried small fires in a small stove and they either do not get the stack hot enough for my taste or if pushed do not last long and just waste wood. I am thinking just break out the long johns and tough it out until a good time to light a fire and get some useful work out of it. To add insult to injury the wind blows a dozen different ways so if burned slow gets blown out and smokes. Maybe the bio bricks get hot enough for the stack yet do not go crazy for heat?