Electrostatic filters are the most effective when it comes to trapping small particles. According to the EPA, HEPA filters are designed to capture 99.97% of all particles, and have an efficiency rating of 17 to 20 on the MERV scale. This makes them a great choice for improving indoor air quality. However, due to their dense filtration material, they cannot be used in grilles or in residential ovens, and are instead used in hospitals and industrial environments.
HEPA filters are ideal for portable or room air purifiers, as their primary function is to remove harmful particles from the air as it passes through the HVAC system. This ensures that the indoor air quality is up to par. HEPA filters can remove 99.97% of contaminants and allergens, including dust particles up to 0.3 microns in size. HVAC air filters with a MERV rating between 5 and 8 can capture particles between 3.0 and 10.0 microns, while those with a MERV rating between 9 and 12 can capture particles between 1.0 and 3.0 microns.
These filters are capable of removing up to 90% of all indoor air particles between 3 and 10 microns, including allergens and odors, as well as viruses. Media filters are also effective at filtering out harmful particles from the air, but they do not restrict airflow as much as HEPA filters do. They have a MERV rating of 2 to 3, so they are suitable for households without pets or respiratory problems. However, they need to be replaced frequently in order to avoid clogging up the HVAC system. Ultraviolet lamps in the filters disinfect the air passing through the HVAC system using their powerful germicidal irradiation.
Air purifiers can also be used in conjunction with an oven air filter in order to improve air quality in a home.