When it comes to air filters, the MERV rating is the industry standard for measuring the minimum efficiency of an air cleaner. The MERV scale ranges from 1 to 16, with higher ratings indicating a greater ability to capture smaller particles. Filters in the MERV 5-8 range can trap particles with a size of 3.0-10.0 microns, with a MERV 5 filter trapping up to 34%, a MERV 6 filter stopping 35-49%, a MERV 7 filter preventing up to 69%, and a MERV 8 filter trapping up to 85% of the particles. ASHRAE recommends using a MERV 6 or higher, while the U.
S. Department of Energy recommends a MERV 13 and LEED recommends a MERV 8 as a minimum. Newer units should not have airflow problems with higher MERV ratings, although older models may work better with a MERV 13 filter installed than when they originally had a MERV 6 filter in the air intake. MERV 5-8 filters provide good filtration and remove most pollen, mold spores, and dust mites.
If you want your air filter to clean the air and handle dust, mold, pollen, and bacteria, then a MERV 8 will do the job. However, filters with MERV ratings higher than a MERV 13 tend to restrict airflow; the higher the MERV rating, the greater the airflow restriction. A higher MERV rating may mean slightly more restricted airflow; however, most current HVAC systems are capable of handling a MERV 11 filter without additional system stress. If you are susceptible to allergies, asthma, or other respiratory conditions, you may want to use a filter with a MERV rating of approximately 10 to 12. When selecting an air filter, consider what contaminants you want it to capture and which MERV rating is best for your home. A filter with an E1 particle capture rate of at least 20%, an E2 particle capture rate of 65%, and an E3 particle capture rate of 85% will obtain a MERV 11 rating.
For maximum air cleaning benefits, consider using a filter with a MERV rating of 13 or higher.