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20x20x4 air filter: actual size, MERV, and price

Printed size 20x20x4 — actual about 19.94 × 19.75 × 4.38 (varies by brand). Pick a pack below.

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Our pickNordic Pure 20x20x4 pleated (3-5/8 actual depth)MERV 8 · Pack of 6$119.99$20.00 per filterLowest verified price per filter (MERV 8–13): $20.00 each, checked 17 OctBuy at Nordic Pure

Match & price

Full answer

A 20x20x4 is a four-inch-class media cartridge for a dedicated filter cabinet — Honeywell F100, F150, and F200 20×20 housings and similar — not a one-inch furnace slot. Buy the printed size 20x20x4. Do not substitute a 20x20x1. The panel is smaller than 20 inches on each face, and actual depth varies more by brand than it does on 1-inch filters.

Full answer

Common published actuals: Honeywell FC100/FC200 replacements about 19.94 × 19.75 × 4.38 (also printed 19.875 square × 4.375), Filtrete deep-pleat 19.75 or 19.88 square × 4.31, Nordic Pure about 19.5 × 19.5 × 3.63. That depth gap is why some Honeywell cabinet replacements are also sold as 20x20x5. A 20x20x5 SKU is not automatically the same cartridge as a 20x20x4. Measure the old cartridge.

OEM model hubs for this size: Honeywell FC100A1011 (MERV 11) and Honeywell FC200E1011 (MERV 13). Related Honeywell media OEM (different face): FC100A1037 (20×25), FC100A1029 (16×25), FC100A1003 (16×20).

Actual dimensions by brand

Actual size by brand

These numbers are copied from manufacturer or merchant product copy, not from a competitor size chart. Thickness is the fit problem on this size: 4-inch actual depth is not one number. A 3.63-inch “20x20x4” will rattle in a Honeywell 4-3/8-inch cabinet; a 4.38-inch cartridge will not slide into a 3-5/8-inch slot.

Brand Nominal Published actual (in.) Source
Honeywell FC100A1011 (MERV 11) and FC200E1011 (MERV 13) 20x20x4 19.94 × 19.75 × 4.38 (19-15/16 × 19-3/4 × 4-3/8) Amazon Resideo FC100A1011 listing “Actual Filter Size: 19-15/16" × 19-3/4" × 4-3/8"”; product-dimensions field 19.94 × 19.75 × 4.38. Filters Fast OEM spec for FC100A1011 and FC200E1011 prints the same 19-15/16 × 19-3/4 × 4-3/8
Honeywell FC100A1011 / FC200E1011 (some Honeywell merchants) 20x20x4 19.875 × 19.875 × 4.375 (19-7/8 × 19-7/8 × 4-3/8) Air Quality Honeywell Store product specs (“Exact Dimensions: 19 7/8 × 19 7/8 × 4 3/8”). Same SKUs; two published figures. Measure if the cabinet is tight
BestAir HW2020-8R (Honeywell F100/F200 replacement) 20x20x4 19.75 × 19.75 × 4.375 (19¾ × 19¾ × 4⅜) Amazon B08HCBH2J7 product description “actual 19¾ × 19¾ × 4⅜”. No public cart price on that listing this check
Filtrete 20x20x4 MPR 1900 / MERV 13 20x20x4 19.75 × 19.75 × 4.31 3M Filtrete product page “Actual filter size is: 19.75 in × 19.75 in × 4.31 in”; Amazon B0DCGRLXXW title and dimensions field
Filtrete 20x20x4 MPR 1550 / MERV 12 20x20x4 19.88 × 19.88 × 4.31 Amazon B09RQC7ML5 title “Actual Size 19.88×19.88×4.31 in” and product-dimensions field
Filtrete 20x20x4 MPR 1000 / MERV 11 20x20x4 19.88 × 19.88 × 4.31 Amazon B09RQBH847 title “Act. Size 19.88×19.88×4.31 in”; bullet “exact dimensions are 19.88 in × 19.88 in × 4.31 in”. Same-SKU product-dimensions field lists 20 × 20 × 4
Nordic Pure 20x20x4 pleated 20x20x4 Approximately 19.5 × 19.5 × 3.63 (19½ × 19½ × 3⅝) JB Tools listings for 20x20x4M8-6, 20x20x4M13-1, and 20x20x4M13-6. Nordic Pure’s own copy says a Honeywell 4-3/8-inch-depth cartridge is their 20x20x5, not this 20x20x4

If you currently run Nordic Pure 20x20x4 (~3.63 deep) and switch to Honeywell FC100/FC200 or Filtrete deep-pleat (~4.31–4.38 deep), you are not swapping like-for-like. The reverse is also true: a 3.63-inch pack will not fill a Honeywell F100/F200 cabinet. Measure the old cartridge. Full method: how to measure.

Amazon Basics: no 20x20x4 SKU with a printed actual turned up in this check, so that brand is omitted rather than guessed.

MERV 8 vs 11 vs 13 (EPA facts)

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 4-inch MERV 13 is not HEPA. We do not claim health outcomes.

MERV EPA average capture efficiency (particle size) Typical 20x20x4 use
8 ≥20% of 1.0–3.0 µm; ≥70% of 3.0–10.0 µm Common pleated 4-inch replacement when the cabinet manual does not call for higher (Nordic Pure 20x20x4M8; BestAir HW2020-8R for Honeywell cabinets)
11 ≥20% of 0.30–1.0 µm; ≥65% of 1.0–3.0 µm; ≥85% of 3.0–10.0 µm Honeywell FC100A1011 OEM media; Filtrete MPR 1000 4-inch deep-pleat is commonly labeled MERV 11
13 ≥50% of 0.30–1.0 µm; ≥85% of 1.0–3.0 µm; ≥90% of 3.0–10.0 µm Honeywell FC200E1011 OEM media; Filtrete MPR 1900 4-inch. Confirm the air handler can take the extra pressure drop. Not HEPA

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. Filtrete MPR 1550 20x20x4 is labeled MERV 12 (price row below); EPA’s table still uses the 8 / 11 / 13 steps shown here.

Where these prices came from

Pack prices checked 30 Aug 2026

Air Quality Honeywell Store prices for the FC100A1011 (MERV 11) 1/2/4/5-packs and FC200E1011 (MERV 13) 1/2/4/5-packs were re-read on 12 Oct 2026; every one matched and all were listed in stock. Nordic Pure card prices were re-read on nordicpure.com on 17 Oct 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. Nordic Pure 20x20x4 rows are the 3.63-inch-depth SKU, not Honeywell 4-3/8-inch cabinet media.

Observed range that day: Nordic Pure 20x20x4 (3.63-inch depth) about $18/filter at MERV 8 in a 6-pack and $24 at MERV 13 in a 6-pack — that SKU is not a Honeywell F100/F200 cartridge. For ~4.3-inch-depth media: Filtrete about $24 (MERV 11 2-pack), $30 (MERV 12 2-pack), $36 (MERV 13 2-pack); Honeywell FC100A1011 MERV 11 about $37–$68/filter depending on pack and merchant; Honeywell FC200E1011 MERV 13 about $72–$95/filter. Amazon BestAir HW2020-8R had no featured offer. Amazon Basics has no 20x20x4 SKU in this check. Nordic Pure Buy buttons go through Awin to nordicpure.com. Factory cart pack prices for listed MERV 8 and MERV 13 packs matching the live JSON were verified 15 Sep 2026 from nordicpure.com.

Where to buy (all stores)

Where to buy

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 20x20x4 SKU. A 20x20x1 is not a substitute. A 20x20x5 may be the Honeywell 4-3/8-inch cabinet cartridge under a different nominal; it is not a 3.63-inch 20x20x4.

Sources

Sources (accessed 30 Aug 2026)

  • EPA MERV table: epa.gov/indoor-air-quality-iaq/what-merv-rating (updated 14 Jan 2026)
  • Air Quality Honeywell Store FC100A1011 1-pack $67.50, 2-pack $115.00, 4-pack $200.00, 5-pack $245.00; FC200E1011 1-pack $94.50, 2-pack $165.00, 4-pack $290.00, 5-pack $360.00 (re-verified 27 Sep 2026; AQHS product:price) (19-7/8×19-7/8×4-3/8)
  • Filters Fast Honeywell FC100A1011 $63.95 (historical; FC200E1011 Filters Fast row removed 27 Sep — wrong SKU href previously)
  • Amazon Resideo FC100A1011 2-pack B0G5B48QP3 $73.84 (buy-box re-checked 16 Oct 2026; sold by Same Day Supply; actual 19-15/16×19-3/4×4-3/8)
  • 3M Filtrete MPR 1900 20x20x4 actual 19.75×19.75×4.31; Amazon (buy-box re-checked 17 Oct 2026) B0DCGRLXXW $53.00 (2-pack; featured offer from Legend Sports NYC; Amazon.com’s own offer $54.13), B09RQC7ML5 $58.99 (2-pack; was $53.27 on 14 Oct; 19.88×19.88×4.31), B09RQBH847 $47.99 (2-pack; was $38.70 on 13 Oct; 19.88×19.88×4.31)
  • Amazon BestAir HW2020-8R description actual 19¾×19¾×4⅜; no featured offer this check
  • JB Tools Nordic Pure 20x20x4M8-6 $107.99, 20x20x4M13-1 $33.29, 20x20x4M13-6 $143.99 (19.5×19.5×3.63)