I have been wondering if the height of the doorway to my living room is original. Ill open up walls soon and should be able to see some evidence. I have a doorway just inside the outside door and the ceiling drops considerably there. It's the same as the hieght of the outside door pretty much. also the doorway into the living room has this drop down at the opening. maybe there were doors in these two places but i see no evidence without opening walls. no door jams in either spot. other rooms also have normal hieght doors but higher ceilings, nothing strange there..
I was thinking that this might be original , or not but since I heat the living room with the fireplace when we are around, I think it reduces the heat loss as there is about 3 feet from ceiling to the top of these doorways and the air in that space is somewhat captive. It can't rush out the open door because that warmer air is lighter and trapped in the house.
so it might make the room warm up a bit faster after someone has opened the outside door or the one to the living room presuming there was one. once the door is closed again there is some "new" cold air in the room from it being open , but then the heat mixes. This captive heated air remains in the room. this helps it come to a more comfortable temperature than it would without these dropped doorways. so high ceilings make the house more comfortable or that's my theory and I'm sticking to it
in my area heat loss was a lot more important than cooling since it isn't super hot in the summer, not like the southern states anyway. they didn't have or need AC, they just opened windows and dealt with it being warm out, but we couldn't live without heat.