When it comes to air filtration, there are two main types of filters that are commonly used: MERV 13 and HEPA. While both of these filters are designed to remove particles from the air, they work in different ways. MERV 13 filters are designed to capture particles larger than 0 or 30 microns, while HEPA filters are designed to capture particles smaller than 0.30 microns. The MERV scale, which ranges from 1 to 20, was developed by leading air quality experts from the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) and is a useful way to compare the performance of different filters.
The following table lists some of the air contaminants that air filters can capture according to the MERV classification. The MERV rating of an air filter describes its efficiency as a means of reducing the level of particles the size of 0.3 to 10 microns in the air that passes through the filter. MERV 17+ filters are also preferred in operating rooms, clean rooms and indoor spaces that require significant air filtration. When looking for the best home air filter, you can find recommendations for both MERV and HEPA air filters.
HEPA filters capture 99.7% of 0.3 micron sized particles, while any air filter in the MERV 11-13 range can capture no more than 75% of 0.3 micron particles. This means that while any air filter is better than no air filter, HEPA filters are more effective at capturing smaller particles than MERV 13 filters. In addition, the MERV qualifies the ability of a filter to trap microscopic and macroscopic particles; FPR ratings only consider the filter's ability to capture or remove particles from 0.3 to 1 micron. It is also difficult for many existing HVAC (heating, ventilation and air conditioning) systems to adopt a MERV 13 because of the increased fan load due to the finer filter medium, which can reduce airflow if the system is not designed to support that type of filter.
Considering the threat posed by the spread of COVID-19 and other germs, updating a building's air filter with a HEPA one is a much more effective measure than simply moving to a MERV 13, considering the small size of the virus (0.06 to 0.12 microns). However, HEPA filters have a major drawback: they limit the amount of air that can pass through them. In conclusion, when it comes to choosing an air filter for your home or business that will provide maximum protection against airborne contaminants, then a HEPA filter is your best option. HEPA filters are more effective at capturing smaller particles than MERV 13 filters and do not limit airflow as much as other types of filters.
