My house has several transfer grilles like this:

Transfer Grille

Except they have no baffles inside them, so light and sound come through into our bedrooms quite easily. I'd like to put in a sound maze like this to block light and sound:

Sound maze

My concern is that I will be restricting air flow enough to impact the HVAC system's effect on these rooms when the door is closed. Is that a valid concern, and if so, what considerations should one make to maximize air flow through a sound maze like this?


2 Answers 2


Yes, it is definitely going to impede the circulation of air. The fan of the HVAC blows the air very gently, so much so that for a large room one register maybe not enough.

For blocking the light you could try hanging a small drape 12 inches in front of the grill.

If the noise is really a nuisance the only effective solution is to connect your grill directly vis a flex duct to the HVAC system.

You can hide it in a cosmetic soffit.

  • 1
    $\begingroup$ I'm trying to get a sense for how much it would impede the circulation of air. A little bit is acceptable, but a more than 50% air flow reduction would be a bad outcome. My understanding is that the air would flow faster through a smaller opening, but then friction and turbulence would reduce the volume of air flowing. I'm trying to figure out to what extent these things offset each other. $\endgroup$
    – John
    Commented Apr 24, 2020 at 14:17

You can maximize airflow by oversizing the output. I am working on a design like this, as per Rod Gervais 'Home Recording Studio' book but having a hard time sourcing the Johns Mansville Linacoustic R300 (rigid duct liner board) that he specifies. This seems to be the only product that has acoustical testing data. I may have to settle for the Linacoustic 1" rolled liner, if I can even get that, but need to consider some other options because this is holding up my HVAC contractor now. Any other ideas? I have two HVAC vents in my home studio live room and don't want the sound to escape to annoy my wife in adjacent rooms downstairs.


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