Basement HVAC Question

[Tifababy]

In the process of finishing my basement, the mechanical inspector told me that I should use a 14"x7" cold air return vent and connect it with a 7" duct to the furnace.

First problem, I can't find any 14"x7" vents, I could only find 14"x6", I'm going to assume that's close enough.

Second problem, I can't find a 7" take off to connect the 7" duct to the furnace. It's easy to find 6" take-offs though. Would it work to use a 6" take-off and then use a 7" to 6" reducer to connect the duct? Or would the reduce defeat the purpose of using a 7" duct?

 

[MikeyIs4Dcats]

is the furnace in a seperate room? It should be sufficient to place an unducted return through the common wall between the main basement room and the furnace room if that is the case.

otherwise, the 6" duct is probably good enough for your home. it's not like you're balancing your system like they do in commercial work.

 

[Tifababy]

I asked the inspector if I could just have a hole in the wall and he said that I needed a 7" duct from the cold air intake back to the furnace. And he kept a list, so he's going to check for everything on the list when he comes back for the second inspection. I wish steel wasn't so f*&@ing expensive right now. Every little elbow or connector is $5 it seems.

 

[MikeyIs4Dcats]

Originally posted by: Tifababy
I asked the inspector if I could just have a hole in the wall and he said that I needed a 7" duct from the cold air intake back to the furnace. And he kept a list, so he's going to check for everything on the list when he comes back for the second inspection. I wish steel wasn't so f*&@ing expensive right now. Every little elbow or connector is $5 it seems.

use flex duct