A lot has changed since COVID-19. But one thing that’s certainly improved and has been a major concern since the pandemic is the air quality.
All offices, businesses, government, and private setups have been trying to find ways to reduce the spread of the virus by air. Face masks have been effective in reducing airborne contact, but air filtration systems with high MERV rating filters are the need of the hour to keep the air safe, clean, and healthy for everyone.
But is the MERV filter enough to combat COVID-19? How does it help prevent the spread of the virus? That’s what we’ll learn in this article.
HVAC systems are usually used in indoor settings to cleanse the air of contaminants, dust, pollen, mold, bacteria, and viruses. These systems use air filters to provide clean air in offices, homes, businesses, and other commercial settings.
The filters have different ratings depending on their ability to clean the air and their efficiency levels, aka the MERV rating.
MERV, or Minimum Efficiency Reporting Values, was developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). The higher the rating, the better the ability of the filter to clean the air and capture pollutants and other particles.
Best MERV Rating
The right MERV Rating for a particular home, office, or facility depends on certain factors. For starters, it depends on the size of the apartment or facility, the number of people, and the air conditions.
So it’s best to go for a higher MERV rating where you can. In HVAC systems, the recommended MERV rating is 13 or higher. However, the only downside of using a high MERV rating is that the air pressure drops. Since the equipment requires more energy to run and the airflow is restricted, it causes less air pressure inside the facility.
The MERV ratings range between 1 and 16, where it goes from low filter efficiency to the highest efficiency. The different filters are meant for different purposes, places, and uses. Here’s a little chart that can help you know which filter to use at home, or in the office.
- MERV Rating 1 – 4: Best for households, small commercial buildings, etc. The filter is effective in capturing 60-80% of contaminants of sizes less than 10 microns.
- MERV Rating 5 – 8: This one works best for small industrial places, residential homes, and offices. The filter is up to 80-95% effective at catching airborne particles sized between 3 to 10 microns.
- MERV Rating 9 – 12: The filter is recommended for use in hospital laboratories, large commercial and residential buildings, etc. These are highly effective (90-98%) at catching the smallest air particles of sizes 1 to 3 microns.
- MERV Rating 13 – 16: These are the most effective filters (95 – 99%) that stop smoke particles, and all other small particles sized between 0.3 to 1 micron. These are recommended for use in hospitals, and large commercial buildings.
MERV Filter Vs. COVID-19
The Coronavirus measures around 0.1 microns in size. It is an airborne virus that attaches to respiratory droplets and spread via air. If we were to use the MERV filter that’s most effective against the virus, the recommended rating is 13 at least. Although MERV rating 11 filters too can capture some coronavirus particles these are not as highly effective as the 13+ rating filters.
A MERV filters with a rating of 13 or higher can efficiently capture 85% of the COVID-19 virus and preserve a healthy airflow inside your home or office.
MERV 14 filters can capture 90% of the small particles and higher ratings can capture higher ranges of viruses. However, make sure to check your unit’s compatibility with the filters.
We can also get MERV filters 17+ in the markets, but most of these are not compatible with your HVAC system or other filtration systems.
So for the HVAC, CDC recommends that MERV 13 works best against the COVID-19 virus.
It’s important to know how coronavirus spreads if we wish to take preventive measures against it.
The COVID-19 infection occurs at short distances. Whenever a person with the disease coughs or sneezes, they release small droplets in the air. The virus travels via these droplets and infects the person within proximity.
If you use the MERV filter at home, if you have a person around who’s already contracted the virus, you’ll likely get it too. Plus, having clean air is not enough. You also need to clean and disinfect the surfaces.
However, the filter is much more effective in an office setting. In the office, people do not live within such proximity as the home. Moreover, the spread of COVID-19 is more likely due to airborne particles than the surface.
So while it’s hard to keep your distance at home, especially with kids, and other loved ones, you can stay a safe six feet distance from your colleagues in the office. As per ASHRAE, using MERV filters with a rating of 13+ helps in such settings.
ASHRAE Recommendations for Coronavirus
ASHRAE has some great advice and prevention techniques to combat the Covid-19 virus using the MERV filters:
- Use MERV 13 or higher filters in large buildings. You may also use small portable air cleaners with MERV 13 or higher filters
- In residential homes use MERV 13 filters instead of the typical 1-inch filter and MERV 16 in place of 2-inch filters.
- For in-duct air cleaning use at least MERV 8 or higher filters for effective disinfecting.
Make note though that the filter is only effective on moving air. So for this to work you need to keep your ventilation system more active. The more the air flows through the filters the more likely the particles – including the coronavirus – will get trapped in the filters.
MERV Vs. HEPA
Now there’s another filter that is highly effective against the Coronavirus, and that is the HEPA filter. The HEPA filter is effective in capturing 99.97% of airborne particles. Compared to the MERV-16 which can effectively capture around 95%, the HEPA filter is much more effective.
Both filters are efficient against small particles of sizes below 1 micron and 0.3 microns.
They can capture most airborne bacteria, mold, viruses, and other pollutants like pet dander, pollen, smoke particles, etc.
However, just like the MERV filter, the HEPA filter also causes a pressure drop. Plus, most ventilation systems are not equipped with HEPA filters. So you can use these in vacuum cleaners and air cleaners.
The HEPA filters are recommended for isolation wards in hospitals and COVID-19 patient wards.
The MERV filter can be used in all residential and commercial facilities. However, since it may cause a drop in air pressure, you should consider the ventilation system’s capacity before using one. If the system is not sustainable to work with low pressures, consider using a portable air cleaner instead of the MERV filter.
Later you may upgrade your ventilation system to meet the requirements of the MERV filters.
In the battle against COVID-19, the MERV filter as a standalone adversary won’t work. You need other means of protection, too, like social distancing, frequent handwashing, sanitization, and using personal protective equipment, etc.