Merv Ratings

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