Trane S9X2 furnace filter sizes
S9X2 furnaces take 16 x 25 x 1 or 20 x 25 x 1 or 24 x 25 x 1 filters, depending on cabinet width and return.
Pick your full model number below for the exact size.
A 16 x 25 x 1 filter (not stated (spec table, upflow model) return) or a 16 x 25 x 1 filter (upflow (bottom or side opening; external) return)
A 20 x 25 x 1 filter (not stated (spec table, upflow model) return) or a 20 x 25 x 1 filter (upflow (bottom or side opening; external) return)
A 24 x 25 x 1 filter (not stated (spec table, upflow model) return) or a 24 x 25 x 1 filter (upflow (bottom or side opening; external) return)