About PadMatch

Humidifier pad and furnace filter cross-reference: find the exact part that fits your HVAC

Two parts on your furnace get swapped every year and neither one's number matches the model on the box: the whole-house humidifier pad, and the furnace air filter. Humidifiers from Aprilaire, Honeywell and GeneralAire use a flat evaporator pad, a water panel or wick, where several look-alikes are a quarter of an inch off. Furnace filters carry a nominal size that is always about half an inch bigger than the filter really is, and three different brands print three different rating scales, MERV, Filtrete MPR and Home Depot FPR, for the same filtration. Pick your humidifier model, furnace air cleaner, OEM part number or filter size and get the exact replacement, the nominal versus actual dimensions, the cross-brand equivalents that fit, and the trap that makes a look-alike part leak or slip past.

Humidifier-pad fitment and dimensions are compiled from AprilAire, Resideo/Honeywell Home and General Filters (GeneralAire) published product pages and owner literature, plus the industry evaporator-pad cross-reference chart. Furnace-filter sizing and MERV/MPR/FPR equivalence are compiled from AprilAire, Honeywell Home and Lennox media-filter product pages, the 3M Filtrete MERV-versus-MPR document, and published nominal-versus-actual size charts, each cited on the page where its data is used.

Fitment is compiled from published manufacturer model lists and the printed cross-reference charts cited on each page. A pad that is the wrong size will let water run past it into the furnace plenum, so measure the pad frame or check the model number stamped on your humidifier before you buy, especially where an Aprilaire panel and a Honeywell pad share a model list but differ by a quarter inch.

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