Replacement Furnace Filter Pads for EAF-2525, Envirosept Electronic HVAC Filter Panel Buy a carton of 12 EnviroSept air filter collector pads package of 12 for your Envirosept Furnace Panel HVAC air purifier model EAF-2525 Panel NOT included . Each a ir purifier furnace filter pad is 23 inches by 22.0 inches. The Envirosept Model 2525 is 24.5 x 24.5 inches x 1 inch. Each filter change uses two replacement pads unless you rotate pads, i.e. remove dirtier on and replace with cleaner one. Replace filter pads monthly or more often if your home or business requires it. Note Measure the panel insert including the black plastic piece to get accurate dimensions of your Envirosept insert. Replacement furnace filter pads cover only the inside mesh part of the furnace air cleaner panel. Replacement furnace filters are made from a custom polywool blend of proprietary fibers without latex or adhesives. We suggest a label on your furnace to remind you of the size. To Replace Furnace Filters Unplug the unit. Remove furnace filter panel from the slot. Open the two retaining clips. Remove both filters. If desired, move the less dirty filter to where the dirtier filter was. Add second filter. Push the clips closed, slide panel into slot and plug in. This item ships from a separate warehouse and may require extra time for delivery.