Nordic Pure 18x24x4 Pleated Air Filters MERV 12 are made of electrostatically charged synthetic materials that attract and capture most airborne particulates in your home. Each time air passes through a Nordic Pure pleated furnace filter， lint， household dust， pollen， dust mites， pet dander， smoke particles， virus carriers， bacteria， mold spores and other contaminants are removed. All Nordic Pure pleated air filters are manufactured using a heavy duty， moisture resistant beverage board frame. There is a metal mesh support grid bonded to the pleats for extra support. MERV 12 furnace air filters are comparable to HVAC filters with the rating of MPR 1500-1900. This high-performance HVAC replacement filter will help keep your air conditioning and heating systems running efficiently， saving money on utilities and costly maintenance.The effective life of your AC air filter depends on both the inside and outside conditions in which you live. It is important to regularly change your furnace air filters especially during any home improvements for fresh， clean air in your home or office. We recommend that you change your air filter every 3-6 months to maintain maximum efficiency and economy.Important Note: Almost ALL furnace filters have a different \"actual size\" than the nominal size printed on the air filter. It's best if you measure your air filter for the EXACT size and compare it to our \"Actual Size\".

Nominal Size: 18 x 24 x 4， Actual Size: 17 1/2 x 23 3/8 x 3 5/8 (17.5 x 23.38 x 3.63)

Nordic Pure recommends changing 4" air filters every 3-6 months

Hypoallergenic， antimicrobial， and electrostatic filter media. Moisture resistant frame.

Ideal for high efficiency air filtration and will help those with moderate allergies and asthma.

Nordic Pure MERV 12 is equivalent to MPR 1500-1900

Made with MERV rated synthetic poly blend pleated media