One of the important tasks of good HVAC preventative maintenance to ensure indoor air quality in homes and buildings is the proper selection and sizing of air filters. Filter There are five popular sizes of air filters: 16 in. x 20 in.; 20 in. x 20 in.; 16 in. x 25 in.; 20 in. x 25 in.; and 24 in. x 24 in. As well as an array of odd sizes for older systems.
<< Difference between a new filter(L) and a used filter that should be replaced(R). "Filter types include electrostatic, pleated, HEPA, and activated carbon. Filters that can be seen through use fibers that work via impingement, which helps capture bigger particles. The fiberglass throwaway filter has little efficiency on small particles that matter. For impurities that go right through most filters, a higher efficiency filter - such as pleated filter - would serve better." Jeff Holt, Past President of the National Air Filtration Association