The AFB Silver MERV 8 furnace / air filter is the most commonly purchased replacement filter by AirFilterBuy. The AFB Silver filters pollen, mold, dust mites, and other particles that are up to the size of pudding mix that you might buy at the grocery store. It will protect your AC / furnace system, while offering adequate filtration to keep your home dust and pollen free. Whenever you are choosing an air filter, make sure that you compare the nominal and actual size of the furnace filter that you are replacing. In this case, the nominal size of the filter is 24x36x2 while the actual size of the filter is 23.5 x 35.5 x 1.75. Generally, the nominal size is rounded and in bigger print while the actual size is in smaller print and in parenthesis to the side. The AFB Silver MERV 8 filter is designed to last 3 months, or 3 times the average fiberglass filter. The most commonly used filter for home or business use is the AFB Silver (Merv 8). AirFilterBuy: Breathe Better!