hang on, lemme go back to this....
raagamuffin The bench will protrude a few inches into a doorway, but that was a compromise we agreed on. I'm messing with her favorite room, moving furniture around, etc to accommodate it !
Is that protruding bench when the bench is pulled out for someone to play? IOW, when the bench is pushed in, it's not protruding? If so, I think that's ok.... But if the bench is always in the doorway, it might be a little bit much...
On the topic of closing vents, I have the vent behind my piano bench permanently closed in the winter, and in the summer with the AC on, I open that vent but I have a damper to direct the airflow from the vent at the wall. My piano's tuning stability tells me it's working. But it's a little chilly there in the winter! That vent is probably 4+ feet away from the edge of the keyboard...