FurnaceFilters.com MERV 8 Return Air Grille Furnace Filters are designed to fit existing air filter grilles. FurnaceFilters.com MERV 8 Return Air Grille Furnace Filters are designed with a 5-inch filter depth that provides nine times the media area of a comparable 1-inch filter, which greatly reduces pressure drop while increasing service life. These filters use a unique knife-edge seal header to prevent bypass, and can last six months to a year in most home installations.
The electrostatically charged, 100 percent synthetic, graduated density media is continuously bonded to a 30-gauge galvanized, corrosion-resistant, expanded metal support grid with an effective open area of 96 percent. The media is resistant to a wide range of chemicals, does not absorb moisture, and will not support microbial growth.
The controlled pleat spacing maximizes surface area and dust-holding capacity and is bonded to the enclosure frame to prevent dust bypass. The enclosure frame is constructed of high wet-strength, moisture-resistant beverage board. The diagonal support members of the frame are bonded to the entering and exiting apexes of each pleat to prevent pleat collapse and filter bowing while preventing air bypass and providing rigidity.