21.9375x21.9375x.75 actual size (22 x 22 x 1 nominal size). The 22x22x1 air filter is an extended surface pleated filter, which exceeds standard air filters with medium efficiency, and are engineered for decreased pressure drop, and increased service life, which reduces HVAC equipment maintenance and energy expenses. The 22x22x1 air filter is classified to ASHRAE test standards 52.2, which ensures that the air filter will capture debris as good or better than original brand 22x22x1 air filters. Pleated design. MERV classified to ASHRAE ratings. 992 cfm flow rate.