What is MERV and how does it apply to air filtration?
MERV is the acronym for Minimum Efficiency Reporting Value which is a number from 1 to 16 that is measures the efficiency of an air filter. The higher the MERV, the more efficient the air filter is at removing particles from the air. At the bottom of the efficiency spectrum a filter may have a MERV of 4 or 5. At the top end, a MERV 14 filter is typically the filter for critical areas of a hospital. The higher MERV rating indicates the filter is better at preventing transfer of bacteria and infectious diseases. Higher MERV filters are also capable of removing higher quantities of small particles. It should be noted however that a higher MERV causes a greater drop in air pressure because filter media becomes denser as efficiency increases.
