The poly wool replacement collector pads for the EnviroSept Furnace filters should be changed monthly. The unit requires 2 pads - front and back. We recommend a "rotation" change, meaning the front pad gets moved to the back, while a new pad gets put in front and the old rear pad gets thrown away. With this method, the EnviroSept furnace filter will work at optimum performance while keeping your indoor air fresh and clean.
EnviroSept Electronic Furnace Filter Replacement Collector Pads – 12 Pack
Replacement collector pads for the EnviroSept Electronic Furnace Filter - 12 pack.