FilterBySize Furnace and AC filter sizes, actual dimensions, MERV

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20x20x1 air filter: actual size, MERV, and price

A 20x20x1 is a one-inch-class square furnace or AC filter. Buy the printed size 20x20x1. The panel is smaller than 20 inches on each face — commonly 19.75 × 19.75 × 0.75 or 19.5 × 19.5 × 0.75, depending on the brand.

MERV 13 SKUs only: 20x20x1 MERV 13.

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 High/Ultra Efficiency (MERV 11 and 13) 20x20x1 19.75 × 19.75 × 0.75 Honeywell Store product specs
Amazon Basics 20x20x1 MERV 11 6-pack 20x20x1 19.75 × 19.75 × 0.75 Amazon product title / actual size field
Filtrete 20x20x1 (MERV 13 / MPR 1900 listing) 20x20x1 Title: 19.62 × 19.62 × 0.78; dimensions field also 19.69 × 19.69 × 0.78 Amazon B005GZ8IG2 — two figures on the same listing; measure if the slot is tight
Nordic Pure 20x20x1 pleated 20x20x1 Approximately 19.5 × 19.5 × 0.75 (19½ × 19½ × ¾) JB Tools listing for Nordic Pure 20x20x1M13-24

If you currently run Nordic Pure (~19.5 square) and switch to Honeywell (19.75 square), expect a snugger slide-in. Measure the old filter if the slot is tight. 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 1-inch MERV 13 is not HEPA. We do not claim health outcomes.

MERV EPA average capture efficiency (particle size) Typical 20x20x1 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.

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.

Listing MERV Pack Price that day Per filter Merchant
Honeywell 20x20x1 Standard Efficiency 8 4 $26.95 $6.74 Honeywell Store
Honeywell 20x20x1 Standard Efficiency 8 12 $71.95 $6.00 Honeywell Store
Filtrete 20x20x1 MPR 1000 Allergen Defense 11 1 $13.44 $13.44 Walmart
Filtrete 20x20x1 MPR 1000 11 2 $21.88 $10.94 Walmart
Filtrete 20x20x1 MPR 1000 11 6 $65.99 $11.00 Walmart / Target
Honeywell 20x20x1 High Efficiency 11 4 $32.95 $8.24 Honeywell Store
Honeywell 20x20x1 High Efficiency 11 12 $93.95 $7.83 Honeywell Store
Honeywell 20x20x1 Ultra Efficiency 13 4 $60.95 $15.24 Honeywell Store
Honeywell 20x20x1 Ultra Efficiency 13 12 $170.95 $14.25 Honeywell Store
Nordic Pure 20x20x1 pleated (reseller) 13 24 $210.59 $8.77 JB Tools

Observed range that day for ordinary pleated 20x20x1: about $6/filter at MERV 8 in a 12-pack, $8–$11 at MERV 11, $9–$15 at MERV 13, with singles costing more than multi-packs. Nordic Pure’s own 20x20x1 factory cart did not load a 1-inch SKU in this check; the JB Tools figure is a reseller snapshot.

Where to buy

We may earn a commission if you buy through links on this page. It does not change the price you pay.

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 20x20x1 SKU.

Sources (accessed 30 Aug 2026)