HEPA is a type of pleated mechanical air filter. It is an acronym for “High Efficiency Particulate Air [filter]" (as officially defined by the U.S. Dept. of Energy). 

- This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).

- The Greentech HEPA air purifier i.e. requires periodic cleaning and filter replacement to function properly. Please follow Greentech's recommendations on maintenance and replacement or subscribe to our notification email.