Orlandos, in Palaces and Houses of Mistra, 1937.
This is a view of the throne-room wing of the palace of Mistra, as seen from the back. There are eight chimneys, elegantly disposed, fed by eight fireplaces in eight individual rooms on the level under the throne room, which has the largest windows. Anastasios Orlandos, in 1937, explained at some length how these chimneys and fireplaces provided heat for the throne room, a space 36.50 meters by 10.43 meters. Architectural historians Charalampos Bouras and Gianluigi Ciotta repeat this information quite flatly, as do the guidebooks and travel books and tourist articles.
So I was thinking about that, half-dozing in an afternoon nap, how it would work: how many people would be needed carrying how many armfuls of logs up the stairs to the second floor to keep the fireplaces fed, how much labor and refuse removal would be constantly visible from the formal front of the palace, the constant procession of people carrying armfuls of wood through those twisty difficult Mistra streets. And then I started thinking about our own fireplace, how there is never a sign in the room above when the fireplace is working below, how I do not feel any heat from the chimney even just above the fireplace -- that sort of thing.
I compared building materials, thickness of walls and floors, even looked up burning temperatures of different kinds of firewood, and calculations for dimensions of fireplaces.
As you can imagine, none of this was helpful, and I remembered reading in Kostis Kourelis' dissertation that archaeologists have found "no evidence of hearths of fireplaces joining or inserted within the wall construction" of medieval houses in Greece. I decided that the famous archaeologists were wrong, but I needed to find support for my unspecialized opinion. I finally wrote a builder of chimneys in England, sent him photographs and architectural drawings and dimensions. He wrote back:
From what I can see, the chimneys were not designed to heat the throne room, as the chimneys are on the outside of the external walls. Had they been on the internal walls, they would have given some heat to the room. I would have thought if they wanted to heat the throne room they would have built the fireplaces in the room
E. Trincanato: Venise: Guide de l'Architecture Mineure (1997).
This was the model followed for the rooms on the second level. Heat in the throne room, if any, would have come from portable braziers. And layers and layers of wool.