Nordic Pure 20x25x4 AC Furnace Air Filter MERV 12, Box of 1
Nordic Pure 20x25x4 MERV 12 Pleated AC Furnace Air Filters: Actual Size: 19-1/2-Inch by 24-1/2 -Inch 3-3/4-Inch. IMPORTANT NOTE: Almost ALL filters are a fraction of an inch smaller than the nominal size printed on the filter. It is best if you measure your filter for the EXACT size and compare it to our "Actual Size" listed above. With the 4-Inch and 5-Inch filters there are many different exact sizes for the different HVAC manufacturers. Because of this, your filter may say 20x25x4 on it but really be the same as our 20x25x5. This is why we ask you to measure your filter so you aren't surprised if the filter doesn't fit! You may also want to look at our Honeywell replacement 20x25x5 filter. Just check the "Actual Size" before ordering. Changing your air filter is the first step in insuring your HVAC system runs at its optimal level this season. Generally, you should change your 4-Inch air filters every 3 to 6 months. Particles in indoor air are measured in microns, which are 1/1000 of a millimeter. A human hair is about 100 microns wide. A MERV 12 Nordic Pure air filter captures airborne particles as small as 0.3 microns! Nordic Pure air filters do not kill germs, however, the filter media does not permit the growth of bacteria or mold. As a result, it is not necessary to add any potentially irritating chemicals to the air filter to kill germs. Nordic Pure air filters are made out of an electro statically-charged synthetic material that draws airborne particulates to it like a magnet. Electrostatic filters help trap airborne particles to protect your family from allergy causing pollen, fine dust, smoke particles, airborne plant spores, bacteria, and some viruses.