HVAC air flow question
Years ago, every room had a cold air return. Today, most HVAC systems have a central return air grill. In order to get air delivery into that room, the bottom of the doors need to be trimmed. I am from the &quot;old school&quot; and still believe in a return grill in every room except the bath room and the kitchen. Why the central return grill, installed cost, of course. Now we see questions as to &quot;how can I reduce the noise coming into a bedroom&quot;? Easy, insulate the walls, add a return in that room, and replace the door which has had the bottom cut off to enhance air flow.  My 2 cents.