Each HVAC air filter comes with a “MERV” rating printed on it. Merv isn’t the name of the guy who packed the shipment; it stands for Minimum Efficiency Reporting Value, a mouthful of a term that expresses the filter’s efficiency at removing airborne particulates inside your home. MERV is a numeral ranging from 1–16. The higher the MERV rating, the smaller the particles it can filter out of your air.
Because the entire volume of air inside your house circulates through the HVAC air filter several times each day, the quality of that filter directly impacts indoor air quality and your healthy household environment. To maintain full filtration efficiency, air filters should be changed monthly. Here’s a brief rundown of MERV categories:
MERV 1–4
These are usually inexpensive fiberglass panel filters, often supplied as original equipment with a new system. They protect moving parts in the system from dust contamination, but otherwise do little to contribute to healthy indoor air quality. Anything smaller than easily visible dust particles slips through the filter media. HVAC professionals commonly refer to filters in this range as “throwaways” that should be immediately discarded.
MERV 5–8
This range is most appropriate for general residential use. These are usually high-quality pleated cotton or polyester filters and remove airborne particulates down to a size of 3 microns. This includes all dust and lint, pet dander, pollen, dust mites and airborne mold spores.
MERV 9–12
Generally recommended for use in homes where occupants have particularly high allergic sensitivities to certain airborne particles and fumes, these filters take out particulates as small as 1 micron.
MERV 13–16
This category comes with a caveat. MERV ratings above 12 are most efficient at filtering air. However, the dense filter media excessively restricts airflow in typical residential systems. Filters in this highest range are generally reserved for hospitals, clinics and other commercial HVAC systems with powerful blowers and air circulation.
Safeguarding indoor air quality since 1922, Paitson Bros. can advise you on the right HVAC air filter for your household.
Our goal is to help educate our customers in Terre Haute, Indiana about energy and home comfort issues (specific to HVAC systems). For more information about air filters and other HVAC topics, download our free Home Comfort Guide or call us at 812-645-6859.
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Paitson Bros
1 (812) 232-2347
Serving the Wabash Valley, IN Area Since 1922