Agree About Not Closing Vents
https://connersuhm791.clarionvale.com/posts/repair-or-replace-your-ac-in-north-fort-worth-with-advice-from-comfort-experts-2
Agree About Not Closing Vents Agree with the point about not closing too many vents. I used to shut them in the guest rooms to cut energy use, and the system started whistling and running longer. Opened them back up and things calmed down