Why 3 Transfer Grilles on Furnace Room Wall. Also do I need a cold air return?


Old 05-30-20, 10:30 AM
Thread Starter
Join Date: Oct 2019
Posts: 18
Received 0 Votes on 0 Posts
Why 3 Transfer Grilles on Furnace Room Wall. Also do I need a cold air return?

Hi, I'm remodeling my basement and noticed the previous owner had 3 transfer grilles on the furnace room wall. I assume it's for better air flow to the furnace. But several years ago when I had a water heater replaced, they installed a duct leading from outside to the furnace room (I believe it's called a combustion air duct?). My question is whether these 3 transfer grilles are needed - 0,1, 2 or all 3? Also,the door for this furnace room is a bifold, so it does not seal the room off as much as a standard door.

I was also wondering if I need a cold air return in this basement. There are no doors - just an open stairway leading to the cold air return upstairs? I'm considering converting one of the transfer grille to a cold air return if needed - although hoping I don't need to do the extra work if not needed!
Attached Images      
Old 05-30-20, 10:41 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,896
Received 1,343 Votes on 1,241 Posts
If they installed a fresh air line in from outside you should be ok.

I see grills at the bottom of the wall and the top.
That was done to draw in cold air from the floor and allow hot air out at the top.
Natural convection.
Old 07-10-20, 05:07 AM
ferd42's Avatar
Join Date: Jul 2020
Location: United States
Posts: 234
Received 17 Votes on 17 Posts
None of the return duct joints appear to be sealed. If they're not, that's a very unsafe condition, especially with an 80% furnace: You could be routinely circulating combustion products to your living space.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: