MERV is an acronym for “minimum efficiency reporting value” and is a measuring system to measure the amount and size of particles that HVAC filters can catch. It was created by the National Air Filtration Association to measure the quality of how well air filters can catch different size particles. The higher the number, the higher the quantity and smaller the size of particles the filter can catch. For example, MERV 11 filters can catch about 85% of particles that are 3 to 10 micrometers, and 65%-80% of particles that are 1 to 3 micrometers.
Here is the chart that was created to track how much a filter can catch:
The ASHRAE 5.2 measures the percentage of particles a filter can pick up in a certain range.
- MERV 1 can pick up less than 20% of particles 3 to 10 micrometers big.
- MERV 16 can pick up more than 95% of particles .3 to 1 micrometers big.
NAFA Technical Committee. (2018, Oct). Understanding MERV. Retrieved from nafahq.org: https://www.nafahq.org/understanding-merv/
National Institute for Occupational Safety and Health. (2003). Guidance for Filtration and Air-Cleaning Systems to Protect Building Environments from Airborne Chemical, Biological, or Radiological Attacks. Department of Health and Human Services, Centers for Disease Control and Prevention. Cincinnati: NIOSH