This is a beautiful piece and heavy. I used it in an unusual way. 
I used this to cover up a large, ugly central a/c return vent. I removed the old metal cover and hung this medallion over the area. It does not affect the filte at all.  It does NOT restrict the air flow either (I checked it carefully) and looks a lot better. I added 2 small screws to the bottom edge (inside edge) to make sure it would hang about /2 inch away from the wall too.