Unlike 1″ filters, whole-house filters don't share one universal nominal-to-actual conversion — the same printed size runs different real dimensions by brand. Find your brand and model below.
| Brand / model | Nominal | Actual dimensions | Source |
|---|---|---|---|
| Honeywell FC100A1029 | 16x25x4 | 15.875 x 24.75 x 4.25 | Reseller consensus |
| Honeywell FC200E1037 | 20x25x4 | 19.875 x 24.75 x 4.375 | Sources disagree |
| Aprilaire 210 / 213 | 20x25x4 | 20.6 x 26.63 x 4 | Manufacturer spec |
| Aprilaire 410 / 413 | 16x25x4 | 16.52 x 29.38 x 4 | Manufacturer spec |
| Aprilaire 201 | 20x25x6 | 21.06 x 25.19 x 7.38 | Manufacturer spec |
| Aprilaire 401 | 16x25x6 | 17 x 28 x 7.47 | Manufacturer spec |
| Lennox X6675 (HCF20-16) | 20x25x5 | ~20 x 24.8 x 4.375 | Reseller consensus |
| Trane / American Standard BAYFTAH23M (TFM235) | 21x23.5x5 | 23.2 x 20.1 x 5 | Manufacturer spec |
| Carrier / Bryant / Day & Night FILCCFNC0016 family | 16x25x5 | 15.375 x 25.5 x 5.25 | Reseller consensus |
| Trion Air Bear 1400 / Supreme (259112-105) | 16x25x5 | 15.75 x 24.25 x 4.94 | Manufacturer spec |
| Trion Air Bear 2000 / Supreme 2000 | 20x25x5 | 19.75 x 24.25 x 4.94 | Manufacturer spec |
| Carrier / Bryant GAPCCCAR2025 / GAPBBCAR2025 | 20x25 (Infinity cartridge) | ~20.7 x 24.4 x 3.5 | Reseller consensus |
| GeneralAire 4551 (ReservePro) | 20x25x5 | 19.625 x 24.1875 x 4.9375 | Manufacturer spec |
| Trane / American Standard BAYFTAH26M (TFM265) | 21x26x5 | ~19.87 x 25.25 x 4.87 | Reseller consensus |
| Aprilaire 216 | 20x25x4 (same cabinet as 210/213) | 20.2 x 25.4 x 3.77 | Manufacturer spec |
| Lennox X8788 | 20x26x5 | 20 x 26 x 5 | Manufacturer spec |