Home › Models › Slant Fin GF-240
What filter does a Slant Fin GF-240 take?
It takes the GeneralAire 1099-20 Water Panel (Legacy Slant Fin fit) — OEM part number 1099-20.
Slant Fin GF-240, whole-house humidifier, whole house.
Lowest verified price: $12.80 — 1 panel, genuine GeneralAire 1099-20 at FM Distributing. FM Distributing shipping terms at checkout. Checked 2026-11-11.
Buy the 1099-20 on Amazon — 1099-20Amazon 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 Amazon price is shown on Amazon; we do not quote it here.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 | GeneralAire 1099-20 Water Panel (Legacy Slant Fin fit) |
|---|---|
| Replacement interval | Replace annually (FM Distributing). |
| Per change | LEGACY: this is the GeneralAire panel for the old Slant Fin GF-200/GF-210/GF-211/GF-220/GF-240/GF-350 humidifiers — Slant Fin's humidifier line is long discontinued, but the panels are still sold. |
| Equivalents | BestAir GF35 / A35 |
Verified prices
| Option | Price | Store & shipping |
|---|---|---|
| Genuine (OEM) 1 panel, genuine GeneralAire 1099-20 | $12.80 | FM Distributing FM Distributing shipping terms at checkout · Checked 2026-11-11 · source |
No aftermarket price was verified for the 1099-20 this pass.
Full record with every price, source and date: GeneralAire 1099-20 Water Panel (Legacy Slant Fin fit) page.
Finding the model number on a Slant Fin
Slant Fin's humidifier line is long discontinued, but its GF-series whole-house units still run on GeneralAire's 1099-20 panel. The model number is on the unit's rating plate inside the furnace room.