The main damper is a thick steel sheet with a handle attached to one end. It slides in and out of the exhaust flue, opening or closing it off. Carbon monoxide would leak back into the house if we closed it with any coals still glowing. (And we've set off the CO alarm a few times when we tried to cheat.)

Yes, two burns a day is much more enjoyable, but it doesn't usually work well with our schedules to burn in the morning.

So, evenings, we enjoy the heat with a book in front of the fire, and dress warmly pretty much all winter.

Even with these small tradeoffs, it still seems like a fine way to collapse early and avoid the rush. We only use our oil furnace when desperate, and we can even cut a substantial amount of our own wood from downed trees.