Nordic Pure 20x25x6 MERV 15 anti-allergen pleated AC / furnace air filters are made of electrostatically charged synthetic materials that are ideal to reduce airborne contaminants in your workplace or office. Each time air passes through a Nordic Pure pleated furnace filter, airborne dust, pollen, mold spores, pet dander, smog, dust mite debris, smoke, and bacteria are captured and removed. Our treated synthetic filter media prevents the growth of bacteria or mold, resulting in a healthier living space. Particles in indoor air are measured in microns; for scale, a human hair is about 70 microns wide. Each Nordic Pure MERV 15 air filter will capture more than 90% of all airborne contaminants from 1.0-10.0 microns, and up to 95% of contaminants from .30-1.0 microns. It is important to note that because of this high filtration and air flow restriction, HVAC systems should be rated to handle filters of MERV 15 and above, which are not typically used in residential settings. This high performance HVAC replacement filter will outperform non-electrostatic fiberglass filters, washable filters, poly disposable filters, and will help keep your air conditioning and heating systems running efficiently, saving you money on utilities and costly maintenance. The effective life of your air filter depends on the inside and outside conditions in which you work. We recommend that you change your air filter every 3 to 6 months to maintain maximum efficiency and indoor air quality.