Best 20x20x1 Furnace Filter

Buy the Amazon Basics 20x20x1 MERV 11 6-pack: $6.07 a filter on November 11, 2026, or $24 to $36 a year. For allergies or pets, buy the Aerostar MERV 13 6-pack at $8.21 a filter, if your furnace manual allows MERV 13.[1]

Check price on Amazon

MERV 8

MERV 8 catches dust, lint and pollen at $5.32 a filter.

Aerostar 20x20x1, 6-pack

$5.32 per filter

$31.93 for 6 · about $21 to $32 a year

A 6-pack of 20x20x1 lasts about 1 to 1.5 years.

Bigger pack, lower price per filter: Filterbuy 12-pack, $4.99 each ($59.88).

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MERV 11

MERV 11 catches fine dust, mold spores and pet dander, and costs $0.75 more a filter than MERV 8.

Amazon Basics 20x20x1, 6-pack

$6.07 per filter

$36.42 for 6 · about $24 to $36 a year

A 6-pack of 20x20x1 lasts about 1 to 1.5 years.

Bigger pack, lower price per filter: BNX 12-pack, $5.79 each ($69.48).

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MERV 13

MERV 13 also catches smoke and bacteria, at $2.14 more a filter than MERV 11.

Aerostar 20x20x1, 6-pack

$8.21 per filter

$49.26 for 6 · about $33 to $49 a year

A 6-pack of 20x20x1 lasts about 1 to 1.5 years.

Bigger pack, lower price per filter: Filterbuy 12-pack, $6.83 each ($81.96).

Check price on Amazon

20x20x1 price per filter is the buy-box price divided by the filters in the pack, read November 11, 2026.[3]

By Erin Rose · Updated

Filtrete vs Filterbuy vs our pick, 20x20x1

Filtrete MERV 11 (MPR 1000) is $9.50 a filter in a 6-pack, $3.43 more than our pick, about $38 to $57 a year. Filterbuy MERV 11 is $5.83 a filter in a 12-pack, about $23 to $35 a year.[3]

Filtrete, Filterbuy and our pick for 20x20x1: pack, price per filter and cost a year
FilterPackPer filterA yearBuy
Our pick: Amazon Basics 20x20x1, MERV 11 6 $6.07 $24 to $36 Check price
Filterbuy 20x20x1, MERV 11 12 $5.83 $23 to $35 Check price
Filtrete 20x20x1 MPR 1000, MERV 11 6 $9.50 $38 to $57 Check price
Our pick: Aerostar 20x20x1, MERV 13 6 $8.21 $33 to $49 Check price
Filterbuy 20x20x1, MERV 13 12 $6.83 $27 to $41 See Filterbuy on Amazon
Filtrete 20x20x1 MPR 1900, MERV 13 2 $13.49 $54 to $81 See Aerostar on Amazon

A year of 20x20x1 is 4 to 6 filters (a change every 60 to 90 days). Each row is the lowest 20x20x1 price per filter we read for that brand and MERV on November 11, 2026.

What 20x20x1 means, and what it measures

19.5 × 19.5 real size, inches label: 20 × 20 depth: label 1 in, real about 0.75 in
The label is the size you order by, and a real 20x20x1 filter is a little smaller, so it slides in.[4]
  • Read the edge of your old filter. It should say 20x20x1: width, height, depth.
  • Depth matters. A 20x20x2 or 20x20x4 filter is too thick for a 1-inch slot. A 20x20x1 that fits leaves no gap and is not bent or crushed.[1]
  • Will MERV 13 work in your furnace? Check the highest MERV on your furnace label or in its manual. MERV 11 saves $2.14 a filter over MERV 13, and a year of MERV 11 runs $24 to $36.

MERV 8, 11 or 13 in 20x20x1: what each catches and what it costs

MERV 13 costs $2.89 more per filter than MERV 8 and $2.14 more than MERV 11. The picks above run $5.32 for MERV 8, $6.07 for MERV 11 and $8.21 for MERV 13.[3]

MERV is a lab score (ASHRAE 52.2), and each 20x20x1 filter below carries one of these three numbers; this EPA table gives the least a filter must trap to earn it.[2]

Minimum capture efficiency by particle size for MERV 8, 11 and 13 (EPA)
MERVSmallest, 0.3–1 microns (smoke, bacteria)Fine, 1–3 microns (fine dust, mold spores)Large, 3–10 microns (pollen, dust)
8not required20% or more70% or more
1120% or more65% or more85% or more
1350% or more85% or more90% or more

The EPA sets one minimum for each MERV number, whatever the brand, and a 20x20x1 filter of about 19.5 x 19.5 inches is held to the same one. Paying more for the same MERV buys a brand name, not a different minimum. MERV is printed by each maker. Filtrete uses its own MPR scale; to convert, see What MERV rating do I need?

All 20x20x1 filters, lowest price per filter first

20x20x1 furnace filters on Amazon with MERV, pack, price and price per filter
FilterMERVPackPricePer filterBuy
Filterbuy 8 12 $59.88 $4.99 See Filterbuy on Amazon
Aerostar 8 6 $31.93 $5.32 Check price
Filterbuy 8 6 $34.17 $5.70 See Filterbuy on Amazon
BNX 11 12 $69.48 $5.79 Check price
Filter King 8 12 $69.96 $5.83 See Aerostar on Amazon
Filtrete 8 12 $69.99 $5.83 See Aerostar on Amazon
Filterbuy 11 12 $69.96 $5.83 Check price
Amazon Basics 11 6 $36.42 $6.07 Check price
BNX 11 6 $39.98 $6.66 Check price
Filterbuy 13 12 $81.96 $6.83 See Filterbuy on Amazon
Show all 21 20x20x1 filters
The rest of the 20x20x1 furnace filters on Amazon, by price per filter
FilterMERVPackPricePer filterBuy
Filterbuy 11 6 $43.98 $7.33 Check price
Simply 11 6 $44.51 $7.42 Check price
Simply 13 4 $31.96 $7.99 See Aerostar on Amazon
BNX 13 6 $48.96 $8.16 See Aerostar on Amazon
Aerostar 13 6 $49.26 $8.21 Check price
Filterbuy 13 6 $49.98 $8.33 See Filterbuy on Amazon
Simply 13 6 $52.27 $8.71 See Aerostar on Amazon
Filtrete 11 6 $56.99 $9.50 Check price
Aerostar 13 4 $37.99 $9.50 Check price
Filterbuy 13 4 $40.96 $10.24 Check price
Filtrete 13 2 $26.99 $13.49 See Aerostar on Amazon

Each 20x20x1 filter's size, MERV and pack count come from its listing title. 20x20x1 prices read November 11, 2026; they change, so the button shows today's.

Frequently asked

What MERV should I buy for a 20x20x1 furnace?
MERV 11 for most homes: $6.07 a filter here, $0.75 more than MERV 8. The EPA says to choose at least MERV 13 or as high as your system will accommodate, and MERV 13 costs $2.14 more a filter than MERV 11. [2][1]
Will MERV 13 work in my furnace?
The EPA says most furnaces take MERV 13 without problems when the filter is changed often. If your manual names a lower top MERV, buy MERV 11 and keep the $2.14 a filter. [1]
What is the real size of a 20x20x1 filter?
Real size is 19.5 to 19.75 inches each way and 0.75 deep. Modern Air Filters lists about 19.5 x 19.5 x 0.75; the Amazon Basics and Aerostar listings print 19.75 x 19.75 x 0.75. Measure your slot, or look for 20x20x1 on your old filter. [4][3]
Can I use a 20x20x2 filter in a 20x20x1 slot?
No. A 20x20x2 filter is twice as deep as a 20x20x1 slot, so match all three numbers on the edge of your old filter.
How often should I change a 20x20x1 filter?
The EPA says makers recommend a new 20x20x1 filter every 60 to 90 days. At $6.07 a MERV 11 filter, that is $24 to $36 a year. Change a 20x20x1 sooner with pets, smoke or a lot of dust. [1]
Is a bigger pack of 20x20x1 filters cheaper?
For MERV 11, the Amazon Basics 6-pack is $6.07 a filter and the BNX 12-pack is $5.79, $0.28 less a filter. A 12-pack of 20x20x1 is 2 to 3 years of filters, so buy it only if you will use them. [3]

Where these numbers come from

  1. 1

    U.S. EPA: Guide to Air Cleaners in the Home (furnace and HVAC filters)

    Read October 28, 2026. "Select a filter rated at least MERV 13 or as high as your system will accommodate"; "Most furnaces and HVAC systems can accommodate a MERV 13 filter without creating equipment problems, provided that the filter is replaced frequently"; makers "typically recommend replacement every 60 to 90 days"; the filter should fit snugly, with no bending or crushing.

  2. 2

    U.S. EPA: What is a MERV rating?

    Read October 28, 2026. The capture table below is copied from the EPA table for MERV 8, 11 and 13.

  3. 3

    Amazon.com product listings (size, MERV and pack from each listing title; price, seller and stock from the buy box)

    Buy boxes read November 11, 2026. Prices change; the button shows today's. Filtrete's MERV equivalents (MPR 1000 = MERV 11, MPR 1900 = MERV 13) are taken from each listing's title.

  4. 4

    Modern Air Filters: 20x20x1 air filter

    Read November 3, 2026. Actual size about 19.5 x 19.5 x 0.75 inches; order by the nominal 20x20x1; MERV 8, 11 and 13 pleated filters; a pleated filter typically lasts 60 to 90 days.

Related: furnace filters in every size · what MERV rating do I need? · is MERV 13 too restrictive? · 4-inch filters for Aprilaire, Honeywell and Lennox cabinets