Indoor Air Quality

What MERV Rating Is Best For Filtering COVID Virus Particulates?

Filters with a high enough MERV rating can reduce the spread of COVID virus particles.

December 1, 2021
Last Updated On:
May 12, 2022
Last Updated On:
May 12, 2022

The rise of the coronavirus has prompted business owners, government offices, and schools to reassess their air quality and to find potential ways to reduce the airborne spread of COVID-19. The coronavirus disease, which is caused by the SARS CoV-2 virus, can be transmitted in many ways, one of them being through respiratory droplets in the air (i.e., talking, exercising, coughing, or coughing sneezing). Air filtration technology with a high MERV rating can reduce the rate of COVID in the air. Therefore, implementing an air filtration system or air purifier can help these community-serving facilities reopen to the public during the ongoing pandemic.

What is MERV Rating?

Air filters are technologies that are added to heating, ventilation, and air conditioning (HVAC) systems and used in portable devices to clean the air we breathe. These systems are typically used in indoor spaces. High-efficiency HVAC systems can improve indoor air quality (IAQ), improve workplace productivity, reduce sick building syndrome symptoms, and provide cleaner air environments in hospitals and industrial settings, among other places. To find the most effective product at keeping the air clean, you should look for one based on its efficiency rating scale. In the HVAC industry, we call it a MERV rating

MERV stands for Minimum Efficiency Reporting Values, and it is a test method developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). In general, finding a filter with a higher MERV rating will correlate to higher efficiency in capturing airborne particulate and pollutants.

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. HEPA, which stands for high-efficiency particulate air, is a highly absorbent media filter that meets the standards of HEPA. For the European Standard, a True HEPA filter will filter the air and capture at least 99.95% of particles of 0.3 microns in size. A True HEPA reports that the filter captures at least 99.97% of particles at least 0.3 microns in size for the DOE standards.

What MERV Rating Should I Use?

The MERV rating you decide to use should depend on your facility requirements. Not every building type requires the air to be super clean. However, getting a filter with a high MERV rating will only help. For HVAC systems, ASHRAE recommends a filter with a minimum MERV rating of 13, but MERV 14 or greater is preferred. Of course, this can only happen if your HVAC system has MERV 13+ compatibility. 

With the increase in air filtration provided by higher MERV ratings, there will also be a pressure drop, reducing airflow through the system and, therefore, more energy expenditure to keep up with the fan resistance. If you can’t get MERV 13 in your HVAC system, get the highest filter possible. You can also add a portable air filter with a high MERV rating. Be sure that any filter you purchase is tested under ISO 16890.

MERV Ratings Explained

MERV ratings range from 1-20, with 20 being the highest, most effective filter you can purchase. You can view this MERV rating chart so you know you’re buying the right filter. MERV ratings 1 to 4 are generally only used as pre-filters but can be found in many typical applications like commercial buildings, furnaces, and window AC units. These filters capture particles at 10.0 microns in size, including pollen, dust mites, and carpet fibers.

Filters rated 5 to 8 are better pre-filters for commercial and residential spaces and can also collect mold spores, dust lint, and cement dust. Once you pass MERV 10, the filter can capture particles smaller than 3.0 microns in size. MERV 13 and above might be used as a final filter in clean rooms, surgical wards, hospital inpatient care, and smoking lounges. MERV 14 and greater can capture particles that are even smaller than previous MERV ratings, which range from 0.3 to 1.0 microns in size. 

The most commonly used filters are the MERV 13 to 16 range, which will capture everything mentioned above, including lead, humidifier, nebulizer, coal dust, Legionella, insecticide dust, and copier toner sneeze nuclei, auto fumes, and bacteria. MERV 16 is the highest filter that you can purchase, but your AC system might not be able to handle that. 

Some high-end filtration systems can take MERV 17 to 20, and those will be used in clean rooms, for radioactive and carcinogenic materials, and in facilities that manufacture pharmaceuticals. MERV 17 to 20 will also capture virus carriers, carbon dust, combustion smoke, radon progeny, and microscopic allergens (particles sized 0.3 of a micron).

Are MERV 13 Filters Your Best Choice?

Which MERV rating is Best For the COVID-19 Virus?

Research suggests that the COVID virus particle, the SARS-CoV-2 virus, measures around 0.1 microns in size. They travel through the air by attaching to a respiratory droplet that is 1 micron in size or larger. Therefore, a filter with a MERV rating of at least 13 would efficiently capture the COVID-19 virus particles, and it could help reduce the spread of COVID-19 indoors. 

Filters with a MERV rating of 11 can capture some coronavirus particles (65%), but MERV 13 are more effective, removing 85% of particles at 0.3 microns. The higher you go, the more efficient the filter is. MERV 14 can capture 90% of the identical particles (range 1 to 3 microns). Of course, getting a filter higher than 13, like a MERV 17+, will be effective. However, MERV 17 filters do not always work for the air filtration systems that you are using. 

Several filters can be used for removing virus particles, but one of the most common is HEPA filters. Consider using a HEPA filter in conjunction with MERV 13+ rated filters. HEPAs are most efficient at capturing 0.3-micron particles, also known as “the most penetrating particle size” or MPPS. They are highly effective (99.97% or 99.95% depending on the standards used) at capturing the airborne viral particles associated with SARS-CoV-2. 

MERV 13 Filter For HVAC

Choose the Best MERV Filter for Your Business

A good MERV rating efficiency will improve indoor air quality and reduce the spread of virus particles. While there is no standard recommended MERV rating for reopening during the COVID-19 pandemic, ASHRAE recommends a MERV rating of 13+, which is designed to capture particles of 1 micron in size would be effective at capturing the COVID-19 virus particles indoors. 

Which MERV rating is best for businesses? With a portable air purifier through Sanalife, you can access easy-to-use air filtration systems with MERV ratings 13+. These convenient devices come with multiple filters to trap harmful particles and eliminate a large number of COVID particles from indoor air. See today the Sanalife difference in your business. 

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