Every furnace filter has a Minimum Efficiency Reporting Value (MERV) rating, which measures how efficiently the filter captures particles of specific sizes that pass through it as your furnace operate...
s. MERV ratings range from 1 (least efficient) to 16 (extremely efficient). Particles are measured in microns and range from carpet and textile fibers (greater than 10 microns) to microscopic bacteria (less than 0.3 microns). This infographic goes into greater detail of what MERV ratings are and by the end of it, you'll have a clear understanding of just what they are.
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