The Minimum Efficiency Report Value (MERV) rating for an air filter measures how effectively the filter prevents dust and other contaminants from passing through the filter into the air stream. MERV ratings range from 1 to 16, with higher ratings indicating a more efficient filter. A MERV 14 rating indicates that the filter is capable of trapping 90% or more of particles in the 1.0-10.0 micron range. It can also prevent up to 84% of 0.3-1.0 micron particles from passing through. These air filters are incredibly efficient, but they are not recommended for residential use.
They are large, bulky, and designed primarily for heavy-duty filtration in locations such as medical facilities. Air filters with MERV ratings higher than 13 also tend to restrict airflow because they have smaller pores to capture smaller particles. This reduction in airflow to your HVAC system can worsen the air quality in your home, as well as put too much pressure on your air conditioning system. MERV 8-10 filters capture more of the large particles and at least half of the smallest particles, such as pollen, dust mites, and mold and fungus spores. In general, filters with a MERV 16 rating or lower are considered HVAC system grade filters for residential, commercial, and general hospital use.
Anything higher than a MERV 13 is normally found in a hospital environment, where air sanitation is of the utmost importance. Schools often use MERV 13 air filters to provide clean learning environments for their students and staff. Using an air filter with a MERV rating higher than recommended by the manufacturer of your oven or air conditioner may impair its performance. MERV 11-13 air filters are a kind of midpoint between the cheapest and the most expensive. Filters with higher MERV ratings trap small particles more effectively than filters with lower MERV ratings. Therefore, if someone in your household has allergies or a respiratory condition, you should consider purchasing a higher MERV air filter. MERV stands for Minimum Efficiency Report Value, developed by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE).
Oh MERV, if there's any clearer reason it's going to be replaced by ISO 16890, it's the 95% confusion of air filters.
