Nordic Pure 20x25x6 MERV 13 anti-allergen pleated AC / furnace air filters are made of electrostatically charged synthetic materials that are ideal to reduce airborne contaminants in your home or business. Each time air passes through a Nordic Pure pleated furnace filter, airborne dust, pollen, mold spores, pet dander, smog, dust mite debris, and tobacco and fireplace smoke are captured and removed. Our filter media prevents the growth of bacteria or mold, resulting in a healthier living space. MERV 13 air filters are comparable to air filters with the MPR rating of 1900-2200, FPR rating of Blue, and APR rating of Diamond. Particles in indoor air are measured in microns; for scale, a human hair is about 70 microns wide. Each Nordic Pure 6” MERV 13 air filter will capture more than 90% of 1.0-10.0 micron contaminants and up to 75% of .30-1.0 micron contaminants. 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. 6” filter racks vary in depth from unit to unit. Please measure the exact inside depth of your filter rack and compare that measurement to our actual depth size to ensure a proper fit. The effective life of your air filter depends on the inside and outside conditions in which you live. We recommend that you change your air filter every 3-6 months to maintain maximum efficiency and indoor air quality.