MERV means Minimum Efficiency Reporting Value which was developed by the American Society of Heating, Refrigeration and Air Conditioner Engineers - ASHRAE. MERV values vary from 1 to 16. The higher the MERV value is the value the more efficient the filter will be in trapping airborne particles.
MERV values by particle size:
|MERV||Min. particle size||Typical controlled contaminant||Typical Application|
|1–4||> 10.0 μm||Pollen, dust mites, cockroach debris, sanding dust, spray paint dust, textile fibers, carpet fibers||Residential window AC units|
|5–8||10.0–3.0 μm||Mold spores, dust mite debris, cat and dog dander, hair spray, fabric protector, dusting aids, pudding mix||Better residential, general commercial, industrial workspaces|
|9–12||3.0–1.0 μm||Legionella, humidifier dust, lead dust, milled flour, auto emission particulates, nebulizer droplets||Superior residential, better commercial, hospital laboratories|
|13–16||1.0–0.3 μm||Bacteria, droplet nuclei (sneeze), cooking oil, most smoke and insecticide dust, most face powder, most paint pigments||Hospital & general surgery|