American Standard XT80 (TDD1 -H) furnace filter sizes
XT80 (TDD1 -H) furnaces take 16 x 20 x 1 filters, depending on cabinet width and return.
Pick your full model number below for the exact size.
2 filters, each 16 x 20 x 1 (downflow top (external, in return duct)) or 2 filters, each 16 x 20 x 1 (downflow top (external, in return duct))