Several types of air filters are common in commercial HVAC systems: 1) Fiberglass filter. This throwaway air filter is the most common type. 2) Polyester and pleated filters. 3) High efficiency particulate arrestance (HEPA) filters. 4) Washable air filters.

Generally, high-performance dry filters can catch up to 99% of the incoming contaminants due to the smaller micron size of the filter media, while oiled filters catch about 98% of what passes through a minute difference, but a difference none-the-less.