What filter does a AprilAire 440 take?
It takes the AprilAire Water Panel #12 — OEM part number 12.
AprilAire 440, whole-house humidifier, whole house.
Lowest verified price: $6.38 — 1 panel, genuine AprilAire 12RP at Zoro. Zoro shipping terms at checkout. Checked 2026-11-11.
Buy the 12 on Amazon — 12Amazon search for the exact part number (no single listing is endorsed). Amazon price is shown on Amazon; we do not quote it here.
The part, in brief
| Part | AprilAire Water Panel #12 |
|---|---|
| Replacement interval | Replace every year or every 6 months (AprilAire guidance via DiscountFilters); older-model owners twice a year, once after summer. |
| Per change | Sold singly and as a 2-pack (AprilAire 12RP); the AprilAire retail page for this panel also carries the #10 listing ($19.99). |
| Equivalents | GeneralAire GA12, BestAir A12-PR / A12PR2, Filters Fast A12PR |
Verified prices
| Option | Price | Store & shipping |
|---|---|---|
| Genuine (OEM) 1 panel, genuine AprilAire 12RP | $6.38 | Zoro Zoro shipping terms at checkout · Checked 2026-11-11 · source |
| Genuine (OEM) 1 panel, genuine AprilAire 12 | $16.99 | DiscountFilters Free shipping on orders $70+ at DiscountFilters; a fee applies below that · Checked 2026-11-11 · source |
| Genuine (OEM) 1 panel, genuine GeneralAire GA12 (the equivalent panel) | $20.49 | SupplyHouse Free shipping on orders over $99 at SupplyHouse; a fee applies below that · Checked 2026-11-11 · source |
Full record with every price, source and date: AprilAire Water Panel #12 page.
Finding the model number on a AprilAire
Whole-house (furnace-mounted) models: the model number is on the humidifier cover or the side of the cabinet mounted on your ductwork. The water panel number (10 or 35) is printed on the old panel's frame.