Hello all
I am working on a 20 storey office building which has 20125 sf per floor.
I have assigned 1 VAV system /floor area.

I realized that the return air path plays a big role. When I use plenum
return (since I have 4ft plenum in my design), the floor area used by system
in SV-A report is 20125 sf which is correct.

As soon as I change the path to ducted, floor area doubles.

Does anyone know why this is happening?

Any thoughts will be helpful.

Thanks

Deepika

Results with return air path as *plenum- the floor area is correct with
plenum return*

Results with return air path as *ducted- floor area doubles with changing to
ducted*