Originally Posted by ICanFixIt
You can change out the current duct vents to ones that can be closed. They are not expensive. Check Amazon.
Another option is to open the dump valve for the room you want to cool and about 90% of the air will come straight out if the ac unit into that room. It can be quite noisy though.
The duct vents I have do close but the 8 that are in the living area I would have to use a step stool to reach each one to close them. The ones in the bedroom I can reach easily so that is a good option. My A/C setup does not have dump valves on either unit. They are 100% ducted.
Thank you for your input. I can at least control some of it with your suggestion.