If you are prone to allergies, asthma, or other respiratory conditions, then you should consider using a filter with a MERV rating of around 10 to 12. These filters are capable of trapping particles as small as 1 micron, such as car exhaust, pollen, and mold spores.
MERV ratingsare determined by the effectiveness of a filter in filtering particles of different sizes. Specifically, these ratings are based on 12 particles of different sizes from 0.3 to 10 microns (µm) in diameter that were created in a laboratory environment. For reference, a human hair measures approximately 50 µm, and the smallest particles that can be identified by the human eye are approximately 40 µm.
These 12 particles are divided into three different size ranges (E1, E2 and E) and four subranges that exist within each range. The first range, E1, includes particles with a size of 0.3 to 1.0 µm. E2 includes particles with a size of 1.0 to 3.0 µm, and E3 encompasses particles with a size of 3.0 to 10.0 µm. The MERV 12 air filter traps about 89% of particles from 1 to 3 microns and more than 90% of sizes from 3 to 10 microns.
MERV 8 filters are known to be effective at filtering contaminants such as pollen, dust mites, sawdust, mold spores, and lint from the air. However, higher MERV ratings will clean the air even more efficiently. MERV ratings range from 1 to 20, with 1 being the lowest level of filtration and 20 being the highest. If someone in your household suffers from allergies or other respiratory conditions, you may want to opt for a filter with a higher MERV rating.
The MERV 12 filter traps 80 to 89 percent of the 1.0 to 3.0 micron average particles, with an average particle size efficiency of 90 percent or better. The higher MERV rating means that an air filter will capture the most dust, while the lower rating means that a filter will capture the least amount of dust. Filter technology has advanced significantly over the years and MERV ratings are designed to help us determine the most effective and efficient air filter options for heating and cooling systems and more.
Merv 13filters also remove bacteria, tobacco smoke, car fumes, insecticide dust, pet dander and more.
However, higher MERV ratings often mean lower airflow which can make the system work harder and use more energy to do its job. The goal of using a MERV 12 or higher filter is better IAQ: cleaner, more breathable air for everyone, especially those with allergies, asthma, COPD etc. MERV filters 9 to 12 are the best filters that a residential HVAC system can accommodate without serious system modifications. If your home's HVAC system is not capable of handling MERV 13 filters then opt for the next highest possible rating.
Once you understand how the MERV leaderboard works you can choose air filters with the MERV ratings that are right for you.