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.
Below is a table grouping MERV ratings by particle size:
|MERV||Typical controlled contaminant||Typical Application|
|17–20||Best||Virus, carbon dust, sea salt, smoke||Electronics & pharmaceutical manufacturing cleanroom|
|13–16||Better||Bacteria, droplet nuclei (sneeze), cooking oil, most smoke and insecticide dust, most face powder, most paint pigments||hospital & general surgery|
|9–12||Better||Legionella, Humidifier dust, Lead dust, Milled flour, Auto emission particulates, Nebulizer droplets||Superior residential, better commercial, hospital laboratories|
|5–8||Good||Mold, spores, dust mite debris, cat and dog dander, hair spray, fabric protector, dusting aids, pudding mix||Better residential, general commercial, industrial workspaces|
|1–4||Budget||Pollen, dust mites, cockroach debris, sanding dust, spray paint dust, textile fibers, carpet fibers||Residential window AC units|