Goodman GMSS960403AN furnace filter size
This furnace takes a 16 x 25 filter (side return) or a 14 x 25 filter (bottom return), depending on where the return air comes in.
The maker lists width and height only. Most filter racks next to a furnace hold a 1-inch filter; a separate filter cabinet usually holds a 4- or 5-inch one. Check the thickness printed on the edge of your old filter before you order.
Every filter option for this model
Where the filter goes
Not supplied; IO: "Filters can be installed in the central return register or a side panel external filter rack kit (upflows)". Quote: "Filters do not ship with this furnace, but must be provided, sized and installed externally by the installer." (IOG-2009Q)
The maker does not ship a filter with this furnace. The size above is the maker's recommended size at the furnace; if your home has a filter grille in a wall or ceiling, that grille sets the size instead.
How often to change it
General guidance, not from the maker's table: 1-inch filters every 1 to 3 months; 4- and 5-inch filters every 6 to 12 months. Change sooner with pets, smoking or construction dust.
About this model
| Cabinet width | 14 in. |
|---|---|
| Airflow direction | upflow/horizontal |
| Heat input | 40,000 BTU/hr |
| Efficiency (AFUE) | 96% |
| Model number note | trailing letters vary: NOx/gas code (N, X or U) and engineering revision letters (e.g. A, B, AA, BB) |
How to read a Goodman model number
Source
- SS-GMSS96/GCSS96 Product Specifications, rev 10/17 (spec sheet, page 7): document. Read 2026-11-03.
- IOG-2009Q Installation Instructions *MSS9* & *CSS9* Single-Stage Gas Furnace (installation manual, page 33): document. Read 2026-11-03.
Check that the model number on your furnace label matches, and compare with the size printed on your old filter. If they differ, go by the filter that fits your rack.