AC Vent Clearance?

Factual Questions
1

Hi-
I have a question about the amount of clearance need for an AC intake vent. We live in an old home that has been (retro-)fitted with a dual-zone AC system. It’s a SpacePak (or similar) with one air-handler in the crawl-space under the family room and the other in the attic. The problem lies with the intake for the lower-level system.

As I said, the air-handler is located under the family room. The intake vent is located in the floor, and it’s location makes furniture placement very difficult. Would it be possible to place a sofa OVER that vent if it had longer legs? Obviously I know that there needs to be sufficient circulation for the unit to operate properly, but I do not know if 3 or 4 inches of clearance would allow the proper circulation.

Thanks for the help,
-A

2

On a forced air system, you should not obstruct a return vent in any manner that would constrict its regular air flow. If you place furniture over or in front on a return, the total air gap around/under/behind etc. must be equal to or greater than the total area of the vent.

For example, if your return vent is 6" x 8" you must have at least 48 square inches of clearance for air to flow around your furniture.