MERV stands for Minimum Efficiency Reporting Value and is the only standardized filter classification system established by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) in 1987. It measures how effectively a filter prevents contaminants and other particulates from entering a home through the HVAC system. 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. A Merv 11 air filter is able to capture between 65% and 79% of the smallest particles, such as pet dander, smoke, smog, and air pollution from coughs and sneezes. It is recommended for households with children or pets, as well as allergy sufferers.
Air filters with a MERV value of 1 to 4 will trap less than 20% of particles 3 to 10 microns in size, while filters with a MERV rating of 11-13 are more efficient at capturing almost all the largest particles, as well as most of the smaller ones. The higher the MERV rating, the more efficient the filter will be at trapping these particles in the air. However, higher MERV ratings may also restrict airflow due to the thickness of the filter material. Therefore, while higher MERV ratings are more efficient, the recommended MERV ratings for residential filters are between MERV 7 and MERV 13. It is important to measure your air filter to make sure you buy the correct size that is compatible with your HVAC system.
Learn how to monitor your air filter and change it regularly with the right MERV value for your home and family.