Atomic 20x25 FC200E1037 Honeywell Air Filter Replacement - MERV 13 High Efficiency Replacement Media Filter removes over 97 of 3.010.0 micron particles from the air. The Atomic replacement 20X25X4 Air Filter is a MERV 13 rated, high efficiency media air cleaner that can be used in all compatible size air ducts plus Honeywell cleaners that require a 20"W x 25"L x 4"D filter. It will also fit all Aprilaire, Space-Gard, and Trion Air Bear models which use a filter this size. The Atomic replacement for Honeywell FC200A1037 furnace filter features a MERV 13 rating, which is an upgrade from earlier models. The MERV 13 rating denotes that this Honeywell AC filter replacement more efficiently reduces pollen, dust, pet dander, mold spores, dust mites, and other allergens from your indoor air. Removing these airborne particles can help improve allergies and alleviate sinus irritation that can cause watery eyes, itchy throat, coughing, sneezing, and other issues. Aside from the health benefits, frequent and regular filter changes will also extend the life of your heating and cooling system by making it work more efficiently. This Honeywell Compatible HVAC filter should be changed about every 12 months. Note that due to manufacturing variances the size of this Honeywell filter replacement is often about one quarter (1/4") to one half inch (1/2") larger on each side than the official dimensions of 20" x 25" x 4". This filter is also known by Honeywell part number HFC200E1037.