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OK to close a return grill?

347 Views 2 Replies 3 Participants Last post by  Bud9051
I live in a house and since i've been in here I've always noticed the smell of cooking in the kitchen on the ground floor to be the strongest in one bedroom upstairs. I never gave it much thought until today I thought it's odd and decided to do the sniff test. Sure enough, the smell was coming from the grill that's heating the room.

So I'm thinking the culprit must be the return grill in the kitchen. Not sure if this is standard practice but wondering why there's a return grill in the kitchen! Anyways, I'm thinking of closing it with a cardboard, but I'm not sure if that would cause any damage on the furnace and the HVAC system. The house has other return grills, but of course I know it requires a certain amount for the HVAC system to function properly.

How can I determine if closing this one return grill in the kitchen would be OK or not?
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How big is this one return grill?
How big are the others?
Probably not a great idea. But last I checked returns are not allowed in kitchens or bathrooms.
Maybe you can change the location of this one return.
The general guidance I have followed is that the return capacity needs to be greater than the supply. Technically, a room should never be more than 3 Pascals (with respect to outside) positive, and that is a very small number. The supply air is being pushed into a room by something more like 50 Pascals (that's a guess).

Bottom line would be to review all supply and return grill sizes and look for a place to relocate that capacity. Then eliminate the kitchen grill.

If you can find a professional who can do duct design their guidance would be good. Probably not your local furnace service guy. maybe a furnace sales company could point you in the right direction. It is called a "manual S" determination.

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