Can HVAC Filters Reduce the Spread of Germs and Allergens?


The air filters on your central heating and AC unit prevent contaminants from circulating throughout your home. However, air filters are made from several different materials, and they vary in their ability to trap contaminants. This is where an understanding of the MERV rating can come in handy.

The MERV Rating

MERV, which stands for Minimum Efficiency Reporting Value, indicates on a scale of 1 to 16 how well a filter traps contaminants. Air filters between 1 and 4 are the least effective. They can capture anything bigger than 10 micrometers, which includes carpet fibers, large particles of dust, and bugs like dust mites. The cheap fiberglass filters that you might find at a convenience store fall within this range.

Pleated filters are a step up because they boast a MERV rating of 5 to 8. These can trap more because the pleats, or folds, increase the surface area. They can catch anything surpassing three micrometers, which includes:

• Mold spores

• Dust mite feces

• Pet dander

• Hair sprays

Perhaps you want your filters to trap more, in which case you can consider something with a MERV rating around 9 to 12. Anything above this would likely be overkill since we would then be talking about the filters used by hospitals and laboratories. Filters with a rating of 9 to 12 can capture all of the above as well as:

• Humidifier dust, lead dust, and other common dust

• Auto emissions

• Cigarette smoke

• Certain bacteria like Legionella

Rigid cell filters have a MERV rating from 9 to 12. According to the EPA, these filters are on a par with HEPA (high-efficiency particulate air) filters: the same filters that many companies, especially mold remediation companies, use on their vacuums and air scrubbers.

Does Your Indoor Air Quality Need Improvement?

At American Mechanical, Inc., we want to help homeowners improve their indoor air quality. Therefore, we perform filter replacement as a part of HVAC maintenance, as well as offer a variety of indoor air quality products that can make a difference in your humble abode. Give us a call today at (757) 347-8549 to schedule an appointment.