In fact, HEPA air filters are the cream of the crop when it comes to air filtration. With the recommendation of a Merv 13 or higher, many people wonder if a MERV 13 filter meets their 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 increased 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 Merv 8 or MERV 9 filter type. This is where HEPA (High Efficiency Particulate Air) filters come into play.
A HEPA is the cream of the cream of air filters with an equivalent rating of a MERV 17 or higher. A HEPA filter with a MERV 17 rating will trap 99.97% of air particles with a size of 0.3 microns, but will capture an even greater percentage of particles smaller or larger than that size. This is because the 0.3 micron particle is the most difficult particle size to trap, so they test HEPAs with this particle size. This is much better than a MERV 13, and this is the lowest efficiency of a HEPA.
Filtering is a mechanical method of purifying air, which means it works with living and non-living particles. HEPA filters are the most efficient for residential or commercial use, followed by MERV 13-16 filters. However, restricting the air flow of these filters causes a pressure drop and the capacity of the ventilation system must be considered before using them. All air filters are designed to remove dust from indoor air.
A filter with a Merv rating of five to eight will effectively remove a variety of allergens from the air, including dust mites and pollen. If no one in your household has respiratory problems, or if airborne particles are not a particular concern, you can use a basic filter. Minimum Efficiency Report, or MERV, values report a filter's ability to capture larger particles between 0.3 and 10 microns (µm). HVAC filters come in different sizes and efficiency levels, and some systems can only handle certain types of filters.
Even much smaller particles are easier for a filter to trap than particles the size of 0.3 microns; it sounds strange to us, but that's what the EPA says. Consider using filters with high ratings if you suffer from a disease that makes it difficult for your immune system to fight viruses. In fact, HEPA air filters are the ONLY mechanical air filters that are tested and certified to meet a specific efficiency with a specific particle size. When particles from the work environment enter the RESPA air intake port, the particles impact and intercept the filter fibers.
HEPA filters are equivalent to MERV 17 to MERV 20, which restricts airflow too much for a typical HVAC system. If you can't use HEPA, a MERV 13-16 filter is the best option and will continue to offer superior filtration. These measures cannot be overlooked, even if you have the best air filtration and disinfection systems on the market.
ASHRAE or Merv airfilters are tested using dust spot tests that incorporate some fine dust, powdered charcoal and some cotton lint. A logical inference is that if an air filter removes particles down to 0.3-10 microns, it is certainly also at least as efficient at removing larger particles.
An HVAC system that is not compatible with a HEPA filter will not work efficiently, as you will have to try to generate enough power to move air through the filter. Commercial grade air purification manufacturers, such as ISO-Aire, who offer a HEPA air purification system, are often asked about MERV filters. See how HEPA (darker green shaded area) filters compare in effectively capturing microscopic particles in the air to ensure a safe and healthy indoor space for occupants. The scale ranges from 1 to 16, where a larger number indicates greater filter efficiency and the ability to capture smaller particles.
Unfortunately, this isn't the best idea, as some air filters are more effective and efficient than others.