20x25x5 air filter: actual size, MERV, and price

A 20x25x5 is a five-inch-class media filter for a dedicated cabinet — not a 1-inch slot. Do not substitute a 20x25x1. Do not mix it up with 20x25x4. Buy the printed size 20x25x5. The panel is smaller than 20 by 25 by 5 inches. Honeywell F100/F200 replacements (FC100A1037) are a ~4⅜ inch cartridge that Honeywell prints as 20x25x4 and that many merchants sell as 20x25x5. Filtrete’s Air Bear-fit SKUs print about 19.56 × 24.13 × 4.75; Filtrete’s Lennox-fit SKUs print about 19.63 × 24.75 × 4.31; BestAir’s Air Bear replacement prints 19.75 × 24.25 × 4.88.

Same panel, swapped axes: 25x20x5. We treat 20x25x5 as the canonical label. Order 20x25x5.

Five-inch actual depth is not one number. Honeywell 4⅜ cartridges are often sold as 20x25x5. True Aprilaire cabinets are a different family — Aprilaire 210/213 print 20x25x4 (actual 20.6 × 26.63 × 4 on Aprilaire’s shop); Space-Gard 2200/2250 replacements are typically 20x25x6. A 4⅜ Honeywell cartridge is not an Aprilaire drop-in. Measure the old cartridge depth before you order.

Actual size by brand

These numbers are copied from manufacturer or merchant product copy, not from a competitor size chart. Thickness is part of the fit: a Honeywell F100/F200 cabinet is built around a ~4⅜ inch cartridge; a Trion Air Bear cabinet is closer to ~4¾–4⅞. Those are both sold as “20x25x5.”

If you currently run a Honeywell FC100A1037 (~4.38 deep) and grab a Filtrete Air Bear 20x25x5 (~4.75 deep) or a BestAir Air Bear replacement (~4.88 deep), the depth difference is about ⅜–½ inch — that is not a snugger 1-inch slide-in; it is a different cabinet fit. Filtrete’s Lennox-fit 4.31 depth is closer to Honeywell’s 4.38 than the Air Bear 4.75 is. Aprilaire 210/213 (actual 20.6 × 26.63 × 4) is not this panel. Measure the old filter. Full method: how to measure.

MERV 8 vs 11 vs 13 (facts only)

MERV is ASHRAE 52.2, as summarized by EPA. Higher MERV captures a larger share of smaller particles. It also adds resistance. EPA says to pick at least MERV 13 or as high a rating as your system fan and filter slot can accommodate, and to ask an HVAC technician if you are unsure. A 5-inch MERV 13 is not HEPA. We do not claim health outcomes.

Source: U.S. EPA, “What is a MERV rating?”, last updated 14 Jan 2026. Filtrete also prints an MPR number; MPR is 3M’s scale, not MERV. Compare MERV to MERV. Nordic Pure also sells a MERV 12 20x25x5 Honeywell replacement and Filtrete sells MPR 1550 / MERV 12 Air Bear SKUs; those are in the price table, not in this EPA 8/11/13 grid.

Pack prices checked 30 Aug 2026

Amazon rows re-checked 27 Sep 2026 against the live featured-offer buy-box in a headed browser (Buy links now open the exact listing named in each row). Other merchants keep their own stamps.

These are public shelf/cart prices we recorded on 30 Aug 2026. They are not live. Shipping, subscribe-and-save, and store-only deals will move them. Per-filter math is pack price ÷ count, rounded to the cent.

Observed range that day: Nordic Pure’s 4.38-inch-deep Honeywell-replacement 20x25x5 was about $23.85–$32.39/filter at MERV 8, $24.22–$27.00 at MERV 12, and $30.37–$37.79 at MERV 13. For Air Bear-depth (~4.75–4.88) packs: BestAir MERV 11 3-pack $20.66, Filtrete MERV 12 1-pack $24.37–$38.99, Filtrete MERV 13 2-pack $39.67. Filtrete’s Lennox-fit MERV 11 2-pack (actual depth 4.31) was $25.00. Honeywell FC100A1037 OEM — printed 20x25x4, same 4.38 cartridge many stores file as 20x25x5 — was $50–$67.50. Amazon Basics had no 20x25x5 SKU with a printed actual, so that brand is omitted. Filtrete MPR 700 (B0B1P15PTY) titles print the Air Bear actual; Amazon storefront and listing prices disagreed ($53.00 vs $54.04), so that pack price is omitted. Filtrete SlimFit MERV 13 (B0F9LSFKQT) titles print 19.63 × 24.75 × 4.31; that listing was not used for a price row. Walmart Filtrete product pages were not used for prices (several Walmart fetches are bot-checked on this site). Aprilaire’s own shop lists 210/213 as 20x25x4 (actual 20.6 × 26.63 × 4), not 20x25x5 — omitted from both tables. No manufacturer-published Aprilaire 20x25x5 actual was found. Nordic Pure Buy buttons go through Awin to nordicpure.com. Factory cart pack prices for listed MERV 8 and MERV 12 and MERV 13 1/2/4-packs were verified 15 Sep 2026 from nordicpure.com (pick MERV and pack on the factory page).

Where to buy

• Honeywell (OEM FC100A1037) F100/F200 20x25 media cartridge, published exact 19⅞ × 24⅞ × 4⅜. Honeywell prints 20x25x4; many merchants file the same cartridge as 20x25x5. Example: FC100A1037 2-pack.
• Amazon Nordic Pure 20x25x5 MERV 12 2-pack, actual 19.88 × 24.88 × 4.38: B004LURI4Q. Filtrete MPR 1000 / MERV 11 2-pack (Lennox-fit), actual 19.63 × 24.75 × 4.31: B0BVXDDZH7. Filtrete MPR 1550 / MERV 12 1-pack (Air Bear-fit), actual 19.56 × 24.13 × 4.75: B0130EBW1S. Size search: 20x25x5 furnace filter.
• Ace Hardware Filtrete 20x25x5 MPR 1550 1-pack, actual 19.56 × 24.13 × 4.75: Ace 4792701 / NDP03-5IN-2.
• AirFilters.com Custom and stock 20x25x5 cuts: airfilters.com.
• Nordic Pure Factory page (via Awin); published actual ~19.88 × 24.88 × 4.38 — the Honeywell 4⅜ inch cartridge sold as 20x25x5: Nordic Pure 20x25x5HM8-2.

No ranking. Stock and price change. If the slot is an odd fraction that none of these actual sizes match, measure first — that is not a 20x25x5 SKU. A 20x25x1 or 20x25x4 is not a substitute unless the published actual depth matches the old cartridge.