I recently had a contractor create a new wall which cut me off from the rest of the house. There is one AC/Heating vent in the room and when the door is closed it gets very, very hot. As soon as the AC kicks on the room gets very, very cold.
The same contractor later told me that I needed a return air intake to cool the room down.
My contractor is a good carpenter, but his HVAC knowledge seems a bit iffy. The air intake return would doubtlessly help the AC run more efficiently, but - would an air intake vent do anything when the air conditioning is not running?