FilterBySize Furnace and AC filter sizes, actual dimensions, MERV

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20x24x1 air filter: actual size, MERV, and price

Printed size 20x24x1 — actual about 19.75 × 23.75 × 0.75 (varies by brand). Pick a pack below.

MERV 13-only pack page: 20x24x1 MERV 13 (Honeywell Ultra, Nordic Pure).

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Our pickHoneywell 20x24x1 Standard EfficiencyMERV 8 · Pack of 12$76.95$6.41 per filterLowest verified price per filter (MERV 8–11): $6.41 each, checked 17 OctBuy at Honeywell Store

Match & price

Full answer

A 20x24x1 is a one-inch-class rectangle furnace or AC filter. Buy the printed size 20x24x1. The panel is smaller than 20 by 24 inches — commonly 19.75 × 23.75 × 0.75, with Filtrete closer to 19.68 × 23.68 × 0.81 or 19.81 × 23.81 × 0.81 and Nordic Pure about 19.5 × 23.44 × 0.75 (19½ × 23 7/16 × ¾).

Full answer

Same panel, swapped axes: 24x20x1. We treat 20x24x1 as the canonical label. Order 20x24x1. Do not substitute 16x24x1, 20x20x1, or 20x25x1 — those are different printed sizes.

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 part of the fit: 1-inch racks take ~¾ inch media.

Brand Nominal Published actual (in.) Source
Honeywell 1-inch Standard/High/Ultra Efficiency (MERV 8, 11, and 13) 20x24x1 19.75 × 23.75 × 0.75 Honeywell Store product specs (4-pack and 12-pack)
Filtrete 20x24x1 MPR 1000 / MERV 11 20x24x1 19.68 × 23.68 × 0.81 Amazon B07FPB8Q8M, B00TUDHMB8, and B001ETX3F0 titles “Actual Size 19.68 x 23.68 x 0.81 in”
Filtrete 20x24x1 MPR 1000 / MERV 11 (some listings) 20x24x1 19.81 × 23.81 × 0.81 Amazon B07FPB8Q8M, B00TUDHMB8, and B001ETX3F0 product-dimensions fields list 23.81 × 0.81 × 19.81
Filtrete 20x24x1 MPR 700 / MERV 8 20x24x1 19.81 × 23.81 × 0.81 Amazon B0DMTG6FPV title “Actual Size 19.81 x 23.81 x 0.81 in”
Filtrete 20x24x1 MPR 1900 / MERV 13 20x24x1 19.81 × 23.81 × 0.78 Amazon B07FPB8H11 title “Actual Size 19.81x23.81x0.78 in”; same-SKU product-dimensions field lists 23.81 × 0.78 × 19.81
Nordic Pure 20x24x1 pleated 20x24x1 Approximately 19.5 × 23.44 × 0.75 (19½ × 23 7/16 × ¾) JB Tools listing for Nordic Pure 20x24x1M8-24 and 20x24x1M13-24

We did not find an Amazon Basics 20x24x1 listing that publishes an actual-size field, so that brand is omitted rather than guessed. If you currently run Nordic Pure (~19.5 × 23.44) and switch to Honeywell (19.75 × 23.75), expect a snugger slide-in. Filtrete’s published actuals also disagree with each other by SKU. Measure the old filter if the slot is tight. Full method: how to measure.

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

MERV EPA average capture efficiency (particle size) Typical 20x24x1 use
8 ≥20% of 1.0–3.0 µm; ≥70% of 3.0–10.0 µm Common pleated replacement when the manual does not call for higher
11 ≥20% of 0.30–1.0 µm; ≥65% of 1.0–3.0 µm; ≥85% of 3.0–10.0 µm Mid-grade 1-inch pleat (Filtrete MPR 1000 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 Higher-efficiency 1-inch; confirm the furnace/air handler can take the extra pressure drop

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.

Where these prices came from

Pack prices checked 30 Aug 2026

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 for ordinary pleated 20x24x1: about $6.41–$7.35/filter at MERV 8 in multi-packs, $8.75–$9.74 at MERV 11, $10.50–$15.24 at MERV 13. Nordic Pure’s factory 20x24x1 configurator did not print a numeric actual in the fetch; the JB Tools figures are a reseller snapshot with published 19.5 × 23.44 × 0.75. Walmart Filtrete product pages were not used for a cart price. Amazon Filtrete pages were used for actual-size fields, not for this price table. Amazon Basics had no published 20x24x1 actual-size listing. Nordic Pure Buy buttons go through Awin to nordicpure.com. Factory cart pack prices for listed MERV 8 and MERV 13 24-packs were verified 15 Sep 2026 and re-checked 12 Oct 2026 on nordicpure.com (one-time purchase price; same dollars).

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 20x24x1 SKU. A 16x24x1, 20x20x1, or 20x25x1 is not a substitute.

Sources

Sources (accessed 30 Aug 2026)

  • EPA MERV table: epa.gov/indoor-air-quality-iaq/what-merv-rating (updated 14 Jan 2026)
  • Honeywell Store 20x24x1 MERV 8/11/13 pack pages (prices and 19.75×23.75×0.75; each Buy link re-pointed to its exact MERV/pack page, prices re-checked live 28 Sep 2026)
  • Amazon Filtrete B07FPB8Q8M, B00TUDHMB8, B001ETX3F0, B0DMTG6FPV, and B07FPB8H11 titles (actual-size fields). No Amazon Basics 20x24x1 actual-size listing found
  • JB Tools Nordic Pure 20x24x1M8-24 ($176.39) and 20x24x1M13-24 (19.5×23.44×0.75, $251.99)