Undercutting the door seldom provides adequate pressure relief.Refer to Transfer Grille Sizing Table to compute required free area (and grille size) vs.supply airflow." I tried loading it up again and for some reason the doc.won't load up now it maybe my laptop....showed all the different types that these guys are talking about.
Undercutting the door 1" would give you almost 30"s of free area ,with no grille restriction and less sound transmission then grilles in the door. I appreciate your reply, but to me, that's about the same as putting a vent in the door insofar as hearing what goes on in/out of the bedrooms is concerned.
Guess I'm hoping that some cool stuff can be done with thermostats or something like that..... There is a return air in two of the bedrooms, but I'm sure that's not the same as a jumper duct. We have joist or attic space available for all three bedrooms in question.
Can anyone give me a little more detail on what a jumper duct is so I won't sound like the newbie I am when contacting an A/C professional? Is when you install a register in the room, and then run a duct out to(in your case) the hallway.
It's a 3-zone system on an older split-level (three levels) cedar shake house.
The thermostats are all in a hall area, which seemed like a good idea at the time of install.