Reduce light and sound from adjacent rooms sharing air return vents

My two bedrooms upstairs share a wall space for an air return. The wall has an upper and lower return vent. You are able to see directly into the adjacent room from the vents. Is there anything that can be done to block the view and dampen some of the sound between the two rooms?

• Are these vents just to each room or vents from each room that lead to duct work? If for duct work might be able to raise/lower one room's vent opening, so not inline with each room. Feb 16, 2023 at 20:31
• There is no actual duct work in the wall. They used the wall cavity between the studs as the return. Feb 17, 2023 at 16:16
• Assuming when you say upper and lower, that means one room has a return high in the wall and the other low. If the returns are diagonally grated, just rotate them so that you can't see the opposite grate. Feb 18, 2023 at 15:18

You could tent a piece of duct board at a 45 degree angle to the duct in the space between forming an A shape. If the return is served by two intake grills on both sides, the sound would partially bounce into the duct while partially being absorbed by the duct board, and light certainly will not bend around it. It would not be perfect, but it should cut the sound down considerably, and the light down totally. If there is not enough room to do the full A, a single in between would at least reflect sound back and have the same net effect on the light.

``````  |        |
|   /\   |
->|  /  \  |<-
->| /    \ |<-
->|/      \|<-

|    |
|    |
->| || |<-
->| || |<-
->| || |<-

``````

Since the OP stated one of the airflows goes down, you could likely solve it in either direction with a more ellipsoid, as it would be best for airflow. Tape the board at both ends, and insert something in the middle. Turns out drawing an ellipsoid in ASCII is hard :-)

• That's a good idea with forming the A shape. Although I think that would only work for the top vent. If I did the A shape on the bottom vent then that would restrict/block air flow since the air is drawn down towards my basement where my hvac system is correct? Feb 17, 2023 at 16:21
• Flip it over, and put a bottom on it to form a full triangle (So it does not collect stuff) would work exactly the same. or put it in thill toward airflow, but with room around, the angles would not be perfect. but it would still function. Just make sure to leave enough room around it for airflow. ;) Feb 17, 2023 at 16:43
• Actually since the air will be flowing over I will amend the original post... Feb 17, 2023 at 16:46