How Many Return Air Vents Do I Need. I have a 2 ton 1000 CFM system. Return air ducts are necessary for just about every room.
Orangey03 February 15 2013. Keep the doors to each room open so air can properly circulate. Maintain the doors to every room open so air can properly flow.
Generally the square footage of each room will determine the number of vents you need per room because the influence of one vent will be altered when the room is larger than a certain square footage.
You should also have an average of 12 vents - 1 vent. Having several return vents ideally one in every room but even two or three is better than just one creates consistent air pressure. The reason for return air is simple. I have always wondered what that large vent was in my hallway.