What is the MERV Rating and How Does it Impact Air Quality?

Minimum Efficiency Report Values (MERV) is an industry standard that measures the overall effectiveness of air filters. It indicates the ability of a filter to capture particles between 0.3 and 10 microns (µm). A higher MERV rating means the filter can trap smaller air particles, providing finer filtration and preventing 26% of dust particles from passing through. Common airborne pollutants that these filters are tested against include pollen, dust mites, mold spores, dust, pet dander, bacteria, and tobacco smoke.

To determine what MERV rating your unit can support, there are usually a few simple steps to follow. Filters with a higher rating should be changed more frequently (at least every three months) to prevent airflow from restricting airflow, which can cause the system to work inefficiently or even damage it. Although the rating does not exceed MERV 16, high-efficiency particulate air (HEPA) filters trap the smallest particles at a speed even higher than that of MERV 16 and are generally used in surgical operating rooms, clean rooms, and other contexts that require absolute cleaning. MERV 13 filters remove bacteria, tobacco smoke, car fumes, dust from insecticides, pet dander and much more.

They can also filter smoke, airborne viruses, and smog. The higher the MERV rating of a filter, the less dust particles and other contaminants can pass through it. Newer units shouldn't have airflow problems with higher MERV ratings, although older models can work harder with a MERV 13 filter installed than when they originally had a MERV 6 filter in the air intake. If your home's air conditioning system isn't capable of withstanding the MERV 13, opt for a filter with the next highest possible rating.