PadMatch / Every humidifier water panel and furnace filter size
- Nominal size
- 20 x 25 x 4 in
- Actual size
- 19.75 x 24.25 x 3.625 in
- Depth class
- 4 in (media cabinet)
- Typically installed on
- media cabinets for the Aprilaire 1210/2210/4200 and Honeywell F100 20x25
- Sold in MERV
- sold in MERV 8, 11 and 13 as pleated media
Nominal versus actual dimensions for the 20 x 25 x 4 in furnace and HVAC air filter.
A 20 x 25 x 4 in furnace filter has an actual size of 19.75 x 24.25 x 3.625 in. The label is the nominal size, rounded up so the filter is easy to name; the panel is cut undersize so it slides into the slot without binding.
The wide four-inch media filter. It seats in an Aprilaire 1210/2210 or Honeywell F100 20x25 cabinet and takes the Aprilaire 210 or 213 media. It is not interchangeable with the six-inch Aprilaire 2200 filter despite both being 20 by 25.
Order by the nominal size printed on the old filter frame, not by measuring the slot, because every brand runs to the same nominal-to-actual convention.
Find your model
Read the number stamped on the humidifier cabinet or printed on the old pad, then match it below. Confirm the frame size before buying a generic.
- 20 x 25 x 4 in actual sizenominal vs actual dimensions
- 16 x 25 x 4 in furnace filteractual 15.375 x 24.375 x 3.625 in
- Aprilaire 210 media filterAprilaire 210
- Aprilaire 213 media filterAprilaire 213
- Honeywell FC100A1037 media filterHoneywell FC100A1037
- MERV 8 vs 11 vs 13 for a furnace filterwhich rating to buy
Sources: AprilAire 210 MERV 11 air filter product page ยท Aprilaire 213-APR MERV 13 media for 1210/2210/3210/4200 (SupplyHouse)