Goodman GDS8 Technical Manual page 10

PRODUCT DESIGN
This furnace has provisions for the installation of return air filters at the counterflow top return. The furnace will accommodate
the following filter sizes depending on cabinet size:
Optional
Access
Door
Refer to Minimum Filter Area tables to determine filter area requirement. NOTE: Filters can also be installed elsewhere
in the duct system such as a central return.
10
Counterflow Filters
Return Air
Cabinet Width
"A"
Min
Counterflow Top Return
Filter Area
Qty
2
(in )
21
600 2
24 1/2
21
800 2
24 1/2
21
1000 2
24 1/2
Filter Size Dimension "A"
(in) (in)
13.0
15 X 20 X 1
11.3
18.8
20 X 20 X 1
17.7
24.3
25 X 20 X 1
23.4