# AC Vent Clearance? **URL:** \ **Category:** Factual Questions\ **Created:** [October 26, 2011, 9:39pm UTC](https://boards.straightdope.com/t/ac-vent-clearance/600908 "2011-10-26T21:39:57Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Awgrimm](https://avatars.discourse-cdn.com/v4/letter/a/b3f665/32.png) [@Awgrimm](https://boards.straightdope.com/u/Awgrimm)\ **Post date:** [October 26, 2011, 9:39pm UTC](https://boards.straightdope.com/t/ac-vent-clearance/600908/1 "2011-10-26T21:39:57Z")
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 ---
**Author:** ![Sparky812](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@Sparky812](https://boards.straightdope.com/u/Sparky812)\ **Post date:** [October 27, 2011, 7:08pm UTC](https://boards.straightdope.com/t/ac-vent-clearance/600908/2 "2011-10-27T19:08:25Z")
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.