Minimum Efficiency Report, or MERV, values report a filter's ability to capture particulate matter. Filters with MERV-13 ratings or higher can trap smaller particles, including viruses. With the recommendation of a MERV 13 or higher, does a MERV 13 filter meet your needs? A MERV 13 filter is a step in the right direction and captures more particles than a typical MERV 8 filter. However, it's not as good at capturing small virus-sized particles as a HEPA can.
A MERV 13 will trap less than 75% of air particles that are 0.3-1.0 microns in size (coronavirus is 0.1 microns). It is also difficult for many existing HVAC (HVAC) systems to adopt a MERV 13 because of the greater fan load of finer filter media, which can actually cause more harm than good and reduce airflow if your system is not designed to handle that type of filter. On average, many installations are limited to one type of MERV 8 or MERV 9 filter. MERV 13 air filters can filter out bacteria and viruses that can cause infections.
In addition, Camfil is leading the initiative to educate customers about the different MERV ratings and how to know if you are getting what you paid for. The most commonly used filters are the MERV 13 to 16 range, which will capture everything mentioned above, including lead, humidifier, nebulizer, charcoal dust, legionella, insecticide powder and sneeze cores from copier toner, automatic fumes and bacteria. MERV ratings 1 to 4 are generally only used as pre-filters, but can be found in many typical applications, such as commercial buildings, ovens, and window air conditioning units. It's important to note that MERV and HEPA are two different types of air filters, although you've probably seen both related to air filtration.
When using a 4″ MERV 13 filter instead of a 1″ filter, the resistance is reduced and the flow rate increases from 320 fpm to 460 fpm. A filter with a MERV rating of 14 may be able to remove VOCs* from the air, while a different filter with the same rating may not be able to. With a portable air purifier through Sanalife, you can access easy-to-use air filtration systems with MERV 13+ ratings. There are other secondary precautions you can also take to protect yourself from disease, one of which is to upgrade your air filter to a MERV 13.A HEPA filter that is essentially the ultimate solution in the air filter world and far exceeds what a MERV 13 is capable of.
For HVAC systems, ASHRAE recommends a filter with a minimum MERV rating of 13, but MERV 14 or higher is preferred. MERV 14 and higher can capture particles that are even smaller than previous MERV ratings, ranging from 0.3 to 1.0 microns in size. Filters with a MERV rating of 11 can capture some coronavirus particles (65%), but MERV 13 is more effective, removing 85% of particles at 0.3 microns. Therefore, a filter with a MERV rating of at least 13 would efficiently capture COVID-19 virus particles and could help reduce the spread of COVID-19 indoors.
