HVAC systems use filters designed to trap indoor pollutants and allergens. As intake air enters the unit, the filter removes particles, such as dirt, dust, and pollen, before warming or cooling the air and circulating it through vents. MERV is a rating that measures a filter's ability to trap contaminants. Here's what to know about these ratings and how to select the right filter for your home. 

What Do MERV Ratings Mean?

MERV stands for Minimum Efficiency Reporting Values, which measure an HVAC filter's ability to capture particles. Generally, the higher the MERV, the more effectively the filter can trap smaller contaminants. MERV 1 to 8 filters can remove larger particles sized from 3.0 to 10.0 microns, such as pollen, dust mites, and pet dander. 


MERV 8 is typically the minimum standard for residences, as these filters can seize up to 84.9% of these common indoor pollutants. MERV 9 to 12 products trap contaminants with a size of 1.0 to 3.0 microns, including mold and mildew spores. Starting at MERV 13, filters can remove particles sized between 0.3 to 1.0 microns, including bacteria and viruses.

How Should You Choose One for Your Home?

Most residential filters range from MERV 8 to 13. MERV 8 is a good option for preventing allergy flareups and asthma attacks; however, if you want extra protection against allergenic rhinitis, lung infections, and skin rashes, upgrade to a filter with a minimum rating of MERV 9. Additionally, if you want to reduce the spread of airborne illnesses, switch to a MERV 13 filter, which can seize disease-causing viral and bacterial pathogens. 

Keep in mind that products rated higher than MERV 13 are typically made for commercial use. Since they trap more particles, they might become saturated more quickly when used in residential HVAC systems. This can lead to restricted airflow, reducing your unit's efficiency and elevating monthly utility bills. Err on the side of caution by staying within the MERV 8 to 13 range. Additionally, replace your filter at least once every season to promote indoor air quality and maximize efficiency. 


Improve your indoor air quality with help from Anderson Automatic Heating & Cooling. This HVAC contractor provides repairs, maintenance, and new installations, including UL lights and flex filters designed to remove pollutants, to clients throughout Cincinnati. Call (513) 574-0005 to book an appointment and visit the website to learn more about how they can keep your indoor spaces comfortable year-round.