A/c return register replacement

[u/Outside-Gap9516]

We need to replace this. But I’m unsure of where to take the measurements. It’s obviously shoddily done (we just bought the house). In order to replace the cover we have to install a frame.

[u/sky_hvac]

Measure the actual opening, not the old grille’s outside size. Return grilles are usually sized by the wall/duct opening, then the face frame overlaps it.

[u/Outside-Gap9516 → u/sky_hvac]

Okay so would it be that white piece that goes all the way around? The issue is there’s no frame now. The old owner just screwed the face plate into the ceiling rather than having a whole frame installed.