When it comes to air filtration, the Minimum Efficiency Report Value (MERV) rating is an important factor to consider. MERV ratings range from 1 to 16, with higher numbers indicating a more effective filter. MERV 9-12 filters are capable of trapping more than 85% of particles between 3.0-10.0 microns in size. A MERV 9 filter can capture less than 50% of 1.0-3.0 micron particles, while a MERV 10 can stop up to 64%, and a MERV 11 can trap up to 79%.
The highest rating, MERV 12, is capable of filtering out up to 89% of particles from 1 to 3 microns and more than 90% of sizes from 3 to 10 microns. The additional benefits of a MERV 13 filter are that it can filter smoke, airborne viruses, and smog. This makes them particularly useful in heavily polluted areas or areas affected by wildfires, as well as for preventing the spread of disease. However, there is an associated price difference and airflow resistance with any increase in the MERV level.
A MERV 11 filter has a higher efficiency rating than a MERV 8, meaning it can capture finer particles and remove more pollutants from the air. But is a MERV 11 too tall for your needs? Generally speaking, anything under a MERV 13 filter should provide very efficient air purification in a home without affecting airflow. It's important to note that a MERV 11 filter may need to be changed more frequently than a MERV 8 filter. Pleated filters that are MERV 8 to 13, unlike fiberglass, can effectively filter small particles and decrease pressure drop.
If your HVAC has a permanent split condenser fan, however, a higher MERV rated air filter will interfere with it and cause lower airflow. When deciding between a MERV 8 and MERV 11 filter, it's important to consider the benefits and drawbacks of each option. If you're worried about the effects of inhaling fine air particles, then a MERV 11 filter may be the better choice as it can provide additional benefits and capture a wider range of particles that would pass through a MERV 8 filter. Ultimately, the decision should be based on your individual needs and budget.