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AprilAire · humidifier · whole house bypass

AprilAire 448 replacement filter

Use part 12. Usually once a year (manufacturer owner's manual).

The filter that fits

Maker lists this model

AprilAire Water Panel 12

AprilAire 12 Replacement Water Panel

Part number
12
How many
1 per unitpacks: 12 02 (2), 12 04 (4), 12 10 (10)
How often
Usually once a year (manufacturer owner's manual)
Size
15 x 12 x 2 in15 x 12 x 2 in nominal (14.75 x 11.5 x 1.75 actual)
Buy Water Panel 12 on AmazonManufacturer page

Opens an Amazon search for AprilAire Water Panel 12. Check the listing says 12.

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Sources

High confidence: the manufacturer names this exact model on a live page. Each line is the page we read and the day we read it.

  • Which filter fits shop.aprilaire.com Maker's own page checked Oct 1, 2026
    AprilAire 12 Replacement Water Panel For 112, 136, 224, 225, 440, 445, 445A, and 448 Whole-House Humidifiers ... Compatible Models: 112, 136, 224, 440, 445, 445A, 448, Chippewa 224, Chippewa 225
  • How many appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p17 (Models 445-448): 'Remove Water Panel evaporator and Scale Control Insert ... replace with a new Water Panel evaporator'
  • How often appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p11: 'we recommend that you replace the water panel evaporator in your Aprilaire Humidifier annually' ... 'the Water Panel evaporator is usually changed once a year'
  • Size shop.aprilaire.com Maker's own page checked Oct 1, 2026
    Materials: Aluminum, Synthetic Fiber Nominal Measurements: 15H x 12W x 2D (inches) Actual Measurements: 14.75H x 11.5W x 1.75D (inches)
  • Packs shop.aprilaire.com Maker's own page checked Oct 1, 2026
    Package Size 1-pack, 2-pack, 4-pack, 10-pack; SKUs '12', '12 02', '12 04', '12 10'
Show all 8 sources

Which filter fits

  1. shop.aprilaire.com Maker's own page checked Oct 1, 2026
    AprilAire 12 Replacement Water Panel For 112, 136, 224, 225, 440, 445, 445A, and 448 Whole-House Humidifiers ... Compatible Models: 112, 136, 224, 440, 445, 445A, 448, Chippewa 224, Chippewa 225
  2. appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p11: 'For Models 220, 224, 440, 445, 448, 558, 560, and 568 close the bypass damper in the bypass pipe'
  3. shop.aprilaire.com Maker's own page checked Oct 1, 2026
    AprilAire 12 Replacement Water Panel
  4. appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p16 (Model 440): 'Inspect Water Panel evaporator (Stock No. 12) and replace if necessary with colored spot up'

How many

  1. appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p17 (Models 445-448): 'Remove Water Panel evaporator and Scale Control Insert ... replace with a new Water Panel evaporator'

How often

  1. appliancefactoryparts.com Maker's own page checked Oct 1, 2026
    AprilAire owner's manual B2203620A for Models 110, 112, 220, 224, 350, 360, 440, 445, 448, 558, 560, 568, 760 & 768, dealer-hosted copy (Appliance Factory Parts), PDF p11: 'we recommend that you replace the water panel evaporator in your Aprilaire Humidifier annually' ... 'the Water Panel evaporator is usually changed once a year'

Size

  1. shop.aprilaire.com Maker's own page checked Oct 1, 2026
    Materials: Aluminum, Synthetic Fiber Nominal Measurements: 15H x 12W x 2D (inches) Actual Measurements: 14.75H x 11.5W x 1.75D (inches)

Packs

  1. shop.aprilaire.com Maker's own page checked Oct 1, 2026
    Package Size 1-pack, 2-pack, 4-pack, 10-pack; SKUs '12', '12 02', '12 04', '12 10'