When it come's to filters,size does matter so first picture is the better of two whether it look's best or not. Is filter in first picture as big if not bigger than origionally on unit?

The first picture is what I would like it to look like. The rest of the pictures show what I have and wish to modify. If they could make the gap smaller on either side of of the duct, the trim would fit and I would hVe two equal boxes and in the middle of the right box would have the intake vent cover. Aesthetically, to me, it is very unpleasant.

Oops, I mean unpleasing!

New room construction,

Would help to see more of the wall, so that we can understand what the pattern is leading up to this point. However, at the very least, they can enlarge the right side of the duct opening to match the box above, since the register can cover wood as well as duct opening. You will have to check what register cover sizes are available, though...

It is just 36” ogee box molding in the space. For some odd reason, either my device or Houzz is not giving the option to attach pictures. It will only allow me take a picture and attach. The rest of the space is the 36” high ogee box molding. This is the wall that is unlike the rest.

Assuming a white vent cover is to be placed over the intake hole, this doesn’t really bother me. Each wall within a room has restrictions when it comes to wainscoting, from outlets to vents. Once the room is painted and decorated, you really won’t notice the different sizes. Just my opinion.

Thanks, rather! You might be right when it is painted but what bothers me the most is the small rectangular box that is inconsistent with the rest of the molding. Also, there is no molding at the bottom. I just think it could be aesthetically more pleasing. I would like it to be finished as it is in the first picture. This is an area that is very visible and will be seen every day.

You are probably limited by where the sheetmetal is placed because of the stud spacing there. However, the actual "square" opening hole is the determining factor for the cfm, not the larger "rectangle plenum" box. So the "rectangle plenum" box can be slid over or reduced (if not a filtered grille) to center better with the wainscot panel, and remove that small panel above.

Also, this is very poor workmanship in general - it's painted so that means it's final and look at the lippage and gaps between boards.

Thanks, 3on....I agree, a sloppy job and I will work on getting this changed since it sounds like it is doable. I would be much happier if it could look like the first picture of the vertical grill cover and keep the boxes the same size.

Thanks to all who responded. I hope this will work and it is the best option, aesthetically speaking.