return air duct?

I’m pretty sure this is a return air duct, but it seemed to be inactive. It had no filter and was being measured at 93 degrees when the the a/c was operating. All other returns were at 78. Why the three holes too?


Was the register on an Interior or Exterior wall?

House on Slab?

How are the Ducts run?

Does there appear to be a HVAC connection to this area?

On a hallway ceiling.

Slab on grade.

No access to that part of attic.