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Need a different depth?

Same size, deeper filter

Below is 21x21 at 1 naturalaire″. A thicker filter holds more before it loads up, so it lasts longer between changes and puts less strain on the blower — we carry the same width and height in the depths below.

21x21x2 Built to order 21x21x4 Built to order

Ordering for a building? Ask for volume pricing or call 1-866-469-8556.

  • Flanders AAF Pleated Filter Naturalaire Standard MERV 8 Filters (12 pack)
    MERV 8
    AAF Flanders

    NaturalAire Standard MERV 8

    $81.99
    $81.99
    Case of 6 $13.67/filter
  • 16x20x4-1/2 NaturalAire Choice Allergen MERV 8 82655.0451620 (2 Filters)
    MERV 8
    AAF Flanders

    16x20x4-1/2 NaturalAire Choice Allergen MERV 8

    $164.99
    $164.99
    Case of 2 $82.50/filter
  • 20x25x4-1/2 NaturalAire Choice Allergen MERV 8 82655.0452025 (2 Filters)
    MERV 8
    AAF Flanders

    20x25x4-1/2 NaturalAire Choice Allergen MERV 8

    $104.99
    $104.99
    Case of 2 $52.50/filter
  • 25x30x1 NaturalAire Standard MERV 8 84858.012530 (12 Filters)
    MERV 8
    AAF Flanders

    25x30x1 NaturalAire Standard MERV 8

    $180.99
    $180.99
    Case of 12 $15.08/filter
  • 17-1/2x23-1/2x1 NaturalAire Standard MERV 8 84858.01175235 (12 Filters)
    AAF Flanders

    17-1/2x23-1/2x1 NaturalAire Standard MERV 8

    $156.99
    $156.99
    Case of 12 $13.08/filter
  • 24x36x1 NaturalAire Standard MERV 8 84858.012436 (12 Filters)
    MERV 8
    AAF Flanders

    24x36x1 NaturalAire Standard MERV 8

    $188.99
    $188.99
    Case of 12 $15.75/filter
  • 16x25x4-1/2 NaturalAire Choice Allergen MERV 8 82655.0451625 (2 Filters)
    MERV 8
    AAF Flanders

    16x25x4-1/2 NaturalAire Choice Allergen MERV 8

    $104.99
    $104.99
    Case of 2 $52.50/filter
  • Naturalaire MERV 13 custom size air filters
    MERV 13
    AAF Flanders

    Custom Size NaturalAire Healthy Ultra MERV 13 Air Filter

    $248.99
    $248.99
  • 21-1/2x23-1/2x1 NaturalAire Odor Eliminator with Baking Soda MERV 8 air filter
    MERV 8
    AAF Flanders

    21-1/2x23-1/2x1 NaturalAire Odor Eliminator with Baking Soda MERV 8

    $122.99
    $122.99
    Case of 4 $30.75/filter
  • 14x24x1 NaturalAire Microparticle MERV 10 85256.011424 (6 Filters)
    MERV 10
    AAF Flanders

    14x24x1 NaturalAire Microparticle MERV 10

    $89.99
    $89.99
    Case of 6 $15.00/filter
  • 16x20x1 NaturalAire Healthy Ultra MERV 13 Filters (12 pack)
    MERV 13
    AAF Flanders

    16x20x1 NaturalAire Healthy Ultra MERV 13

    $224.99
    $224.99
    Case of 12 $18.75/filter
  • 11-1/2x11-1/2x1 NaturalAire Standard MERV 8 84858.01115115 (12 Filters)
    MERV 8
    AAF Flanders

    11-1/2x11-1/2x1 NaturalAire Standard MERV 8

    $159.99
    $159.99
    Case of 12 $13.33/filter
  • 14x18x1 NaturalAire Healthy Ultra MERV 13 Filters (12 pack)
    AAF Flanders

    14x18x1 NaturalAire Healthy Ultra MERV 13

    $297.99
    $297.99
    Case of 12 $24.83/filter
  • 16x16x1 NaturalAire Microparticle MERV 10 Filters (12 pack)
    MERV 10
    AAF Flanders

    16x16x1 NaturalAire Microparticle MERV 10

    $120.99
    $120.99
    Case of 6 $20.17/filter
  • 20x30x1 NaturalAire Microparticle MERV 10 85256.012030 (6 Filters)
    MERV 10
    AAF Flanders

    20x30x1 NaturalAire Microparticle MERV 10

    $94.99
    $94.99
    Case of 6 $15.83/filter
  • 12x18x1 NaturalAire Healthy Ultra MERV 13 Filters (12 pack)
    AAF Flanders

    12x18x1 NaturalAire Healthy Ultra MERV 13

    $277.99
    $277.99
    Case of 12 $23.17/filter
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