What Is a MERV Rating?

What Is a MERV Rating?

Indoor air quality for commercial HVAC is an issue of growing importance in these COVID-conscious times. This means, among other things, air filtration to remove particulates and organics such as mold and pollen. Good air filtration can also help mitigate the spread of germs, with efficacy being dependent on the filter being used. You must first understand how the filters are rated to make the best decisions.

What Is a MERV Rating?

Minimum Efficiency Reporting Values, or MERVs, rate a filter according to the size of particles it removes from the air. The higher the rating, the more efficient the filtration. MERVs measure for particles between 0.3 and 10 microns in diameter. For example, HEPA and ULPA filters fall under MERV ratings of 17-20 (on a scale of 1-20), while many commercial-grade filters are in the 8-13 range.

It is important to note that even though a higher MERV rating means a more efficient filter, it does not necessarily mean that it is the right filter for the job. Filters with a MERV rating too high for the HVAC system could cause it to work too hard. For maximum effect, without putting undue strain on your system, it is most important that you use the filter rated for your existing HVAC system.

What Is a Good MERV Rating?

The current American Society of Heating, Refrigerating and Air-Conditioning Engineers recommends MERV-13 air filtration as the minimum desirable for commercial buildings, and MERV 14 or better is preferred wherever possible. Generally, for best results, you should always use the highest MERV rating your HVAC system is rated for.

But is MERV 13 good enough to filter out the SARS-CoV-2 virus? Filters with an 11 MERV rating can filter some coronavirus particles, roughly 65%, but a greater MERV rating is recommended. The COVID virus is roughly 0.1 micrometer, but it’s typically embedded in respiratory droplets that are generally 1 micrometer and larger. So, looking at it by MERV ratings, you get the following results:

  • MERV 13 – captures 85% of particles between 1 and 3 micrometers
  • MERV 14 – captures 90% of particles between 1 and 3 micrometers
  • MERV 16 – captures 95% of particles between 1 and 3 micrometers
  • HEPA (MERV 17+) – captures 99.97% of particles larger than 0.3 micrometers

Henick-Lane’s extensive experience with medical and laboratory facilities makes us the premier choice when assessing and improving your building’s air quality.

Henick-Lane, Your Leader for Indoor Air Quality

At Henick-Lane, we have more than fifty years of experience serving the commercial HVAC needs of New York City’s commercial buildings and facilities. Contact us online or call (718) 768-7277 to schedule an indoor air quality assessment.