AprilAire Water Panel 45

Fits these models

• AprilAire 400 400A, 400M, 400KZ, 400MKZ

Part numbers

Genuine part

45

Packs

45 02 (2-pack), 45 10 (10-pack)

How often

Replace at least twice per heating season (manufacturer owner's manual)

What is in it

evaporative water panel (wicking paper reinforced with two layers of aluminum, anti-microbial coating)

Size

13 x 10 x 2 in nominal (12.875 x 9.875 x 1.75 actual)

Sources

• Which filter fits shop.aprilaire.com Maker's own page checked Oct 1, 2026

  AprilAire 45 Replacement Water Panel For 400, 400A, and 400M Whole-House Humidifiers ... Compatible Models: 400, 400A, 400M, 400KZ, 400MKZ

• How many storage.googleapis.com Maker's own page checked Oct 1, 2026

  AprilAire owner's manual B2209190D (09.23), dealer-hosted copy, PDF p9 (Model 400 maintenance): 'Slide the used Water Panel (G) out ... Slide a new genuine AprilAire Water Panel 45 (G) into the scale control insert'; the second panel in the box is a spare

• How often storage.googleapis.com Maker's own page checked Oct 1, 2026

  AprilAire owner's manual B2209190D (09.23), dealer-hosted copy, PDF p7: 'The Water Panel should be changed at least once a year with the exception of Models 400 and 400M which should be changed at least twice per heating season'

• Model variants shop.aprilaire.com Maker's own page checked Oct 1, 2026

  Compatible Models: 400, 400A, 400M; 'AprilAire recommends replacing the water panel assembly twice annually'

• Size shop.aprilaire.com Maker's own page checked Oct 1, 2026

  Materials: Paper - Wicking, Aluminum Nominal Measurements: 13H x 10W x 2D (inches) Actual Measurements: 12.875H x 9.875W x 1.75D (inches)

• What's in it shop.aprilaire.com Maker's own page checked Oct 1, 2026

  The heavy-duty paper panel is reinforced with 2 layers of aluminum and coated with an anti-microbial agent

• Packs shop.aprilaire.com Maker's own page checked Oct 1, 2026

  Package Size 2-pack, 10-pack (no single panel); SKUs '45 02', '45 10'