By Anne Fonda
A MERV rating is a rating for an HVAC air filter that describes how effective it is at filtering out large and small particles (.3 to 10 microns) from the air. A micron is a very small unit of measurement, representing one-millionth of a meter. MERV stands for Minimum Efficiency Reporting Value.
The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) developed a test method to test the effectiveness of air filters. As a result, MERV ratings are now an accepted air filtration rating system.
MERV ratings for air filters range from 1-16 with the higher ratings being more effective at filtering pollutants. In general, HVAC professionals will recommend MERV filter ratings between 8 and 13 for home use. This is because the higher the MERV rating, the more an air filter can restrict airflow. You want to find an air filter that captures pollutants but still lets your HVAC system operate efficiently.
Performance above MERV 16 is high-efficiency particulate air filter (HEPA) performance. HEPA filters are more commonly used in medical facilities and science lab HVAC systems than in residential systems.
Look at the following MERV rating chart for examples of the effectiveness of various HVAC air filters for residential use.
| PARTICLE TYPE | GENERIC 1” MERV 8 FILTER EFFECTIVELY FILTERS DOWN TO 3-10 MICRONS IN SIZE | MERV 11 FILTEREFFECTIVELY FILTERS DOWN TO 1-3 MICRONS IN SIZE | MERV 13 FILTEREFFECTIVELY FILTERS DOWN TO .3-1 MICRONS IN SIZE |
| POLLEN | X | X | X |
| DUST | X | X | X |
| DUST MITES | X | X | X |
| MOLD SPORES | X | X | X |
| LINT | X | X | X |
| BACTERIA/FUNGI | X | X | |
| PET DANDER | X | X | |
| SKIN FLAKES | X | X | |
| HAIR | X | X | |
| LEAD DUST | X | X | |
| VIRUSES | X | ||
| TOBACCO SMOKE | X | ||
| COOKING SMOKE | X | ||
| SMOG | X |
As you can see from the table above, a MERV 8 filter captures only the largest particles. Look at MERV 8 vs MERV 11, for example. By upgrading slightly, your HVAC air filter can capture pet dander, skin flakes, hair, bacteria, and fungi and keep them from circulating through the air in your home.
If you have pets, you will want a better filter than a MERV 8. You may also want to check your air filter more often. Clogged air filters can cause your HVAC system to work harder and may increase allergy and asthma symptoms.
A higher air filter MERV rating will positively affect your home’s indoor air quality (IAQ). An air filter/furnace filter with a higher MERV rating will capture more allergens and pollutants, helping you and your family breathe easy.
If you or someone in your family has allergies or a respiratory condition, you will want to use the highest MERV-rated filter suitable for your HVAC system. The same is true if your outdoor air has a high smog level or wildfire smoke is a known hazard. Work with HVAC professionals to make your decision.
In addition to filtering out everything a MERV 11 filter can, MERV 13 filters can filter out smoke, smog, some airborne viruses, and more. The American Standard QuikBox™ Air Cleaner is a 4.7” filter available in both MERV 11 and MERV 13.
For the ultimate in an HVAC filtration and air purification system, you may want to consider the American Standard AccuClean® Whole Home Air Cleaner, which can remove 99.8% of airborne particles from the air before they enter your HVAC system.
No matter which filter or whole house air cleaner you choose, change your HVAC filters regularly. That can be every 30 days to 6 months days depending on the air filter/air cleaner, the pollen level, and whether you have pets.
Have questions about what air filter MERV rating is best for your HVAC system? Contact your American Standard local HVAC dealer for product recommendations and to schedule HVAC maintenance, repair, or replacement.
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Jennie Bergman, Senior Product Manager, Indoor Air Quality
Air filtration systems utilize an air filter to remove harmful particles from the air you breathe. In most air filtration systems, you can change and maintain filters on your own.
Indoor air quality (IAQ) refers to the level of pollutants and irritants in the indoor air. According to the Environmental Protection Agency (EPA), concentrations of some pollutants are 2-5 times higher indoors than outdoors. And since we spend about 90% of our time indoors, poor IAQ can lead to discomfort and health problems.
Air cleaners reduce the total volume of allergens, dust, pollen, dander, and other harmful particles from the newly cooled or heated air circulating in your home.
Brand name for American Standard Heating and Air Conditioning’s whole-home air filtration that removes up to 99.98 percent of airborne allergens from the filtered air in your home.
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