How do you balance the air pressure in a house?
I have had an excessive dust problem. Many tests have been done. The latest shows when the AC is running and the master bedroom door is closed the rest of the house is under negative pressure. The master bedroom is under positive pressure to the point that it pushes air into plumbing holes under master bath sink.
The house is 2499 sq ft 1 story with 2 AC returns. 1 is located outside master bedroom and the other at end of hall on other side of house.
Do you have any advice on this situation?