In reading about medieval history, one comment I’ve seen is that fireplaces in wall hearths are better than a central fire pit. Why is this? Is it because the fire heats up the walls of the hearth and they radiate the heat out into the room? Or is it some other phenomenon at work?
With a fire pit, clouds of smoke waft throughout the room, before eventually rising to the vent hole in the roof. With a wall hearth, the smoke goes up the chimney.
This actually reduces its effectiveness at heating the room, but the benefits to your lungs make up for it.
Maybe the reduced smoke allows one to build a larger fire and therefore get more heat into the room.
it all comes down to smoke removal. Ever notice how much smoke comes from burning something on the stove? Imagine all the smoke a central fire would make even in a large room. How do you get all of that smoke out of the room without a chimney? Not an easy thing. Nowadays people put wood burning stoves in the middle of rooms for better heat distribution, but they all come with a chimney pipe leading to a side wall or the roof.
People spend lots of tax money on well equipped and responsive fire departments, and are careful to have smoke detectors, evacuation plans, some have extinguishers in their homes - all because you don’t want fire to consume your home, family and possessions.
So, why intentionally bring the shit into your house ?
With a chimney it’s safe® to have lower ceilings, which makes the room easier to heat. Those low low ceilings in olde buildings were due to trying to maintain a livable temperature with the minimum of firewood.
I can’t speak for everyone, but it might have something to do with the fact that fire is an incredibly useful tool.
To the OP’s question, what do you mean by “better”?
Thermodynamic efficiency, convenience, safety, ease of construction, not to mention all the possible interpretations of the “comments” on “medieval history” you refer to, are important considerations in answering your question.
Could you offer something more specific?
The chimney also creates a draught which helps combustion by drawing oxygen through the fire. This means that lower quality fuel like coal can be burned.
When the idea of chimneys was introduced it quickly caught on. The problem was that there were no building regulations so chimneys were built badly and of inappropriate materials like wood. This lead to many houses catching fire.
bob: I don’t think coal would be generally considered a lower quality fuel, if we are using wood as a baseline.
“Better” is simply how the sources state it. What they mean by it is what I’m asking.
This is also why the Franklin stove was such a big deal: it allowed you to build a fire farther out in the room, so the stove would radiate the heat, and the chimney carried the smoke away.
Plus, with a chimney on a Franklin (or any other freestanding stove), you can (almost) close the draft to slow the fire down until it dies off, without trapping all the smoke in the room. You can’t even do that with a fireplace.