Minimum efficiency reporting value, commonly known as MERV rating, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters.

A MERV rating tells you, on a scale of 1-16, how effectively your filter traps the small particles you don't want circulating through your home. The higher a MERV rating, the higher the amount of particles the filter traps