Glenn Herbert wrote:8' deep is really huge! It sounds like it could easily bake all the bread for an entire village. Do you see a chance of actually using the full size of this? If not, I think it would be inefficient to heat it all up to use half or a quarter of the floor. I might consider modifying it to make the baking chamber shorter and converting the front portion to the reburn chamber connected to the chimney.You could probably even do it without significantly altering the existing except for a hole for the chimney, mostly adding new lining.
Is the exterior of the oven exposed so that you could add perlite-clay to it? I expect that would make a lot of difference to comfort.
The plan is for the oven to serve the whole town and beyond! Lots of bread, cookies, but also pizza. To give you an idea, the baker interested currently has a commercial enterprize that does 2000 of the big 5 pound loaves of bread a day. I imagine if she fired it up she would use the oven for several hundred of them plus pizza and other baking. Some years ago it was used to make something like 800 pizzas for a special (one day) event!
The oven is part of the stone walls of the house on two sides but the top can be accessed from one side. I agree a nice layer of insulation would make a lot of difference both in comfort and the amount of wood necessary. My main concern is smoke pollution.