What Are MERV Filters?

MERV filters are a type of air filter that are rated to a common standard – the MERV standard. ‘MERV’ is an abbreviation for Minimum Efficiency Reporting Value. This means the minimum percentage of particles the filter can capture in one pass.

MERV filters are graded from 1 to 20. Higher graded MERV filters are able to capture more particles, as well as smaller particles. This table gives an overview of MERV ratings:


MERV Min. particle size Typical controlled contaminant [2] Typical Application [2]
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[3] 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

Source: EPA.gov


HEPA filters are similar to MERV filters, but have an even higher standard for particle capture.


Learn more: What are HEPA filters and how do they work?

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