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Filtering
HVAC filtration standard is rated in Minimum Efficiency Reporting Value (MERV). The higher the value, the higher amount of smaller sized particles the filter will remove. Notice how thick these filters are in size! These aren’t your 1” filters, my friends!
This home has a MERV-12 filter which is rated to remove 80%-89.9% of 1.0-3.0 micron sized particles and 90% or greater 3.0-10.0 sized particles.
But what do those numbers mean?
A special thank you to "Air Purifier Guide" for their Merv Rating Chart. www.airpurifierguide.org
Furthermore, the United States Environmental Protection Agency states…. "Medium efficiency filters with a MERV of 5 to 13 are reasonably efficient at removing small to large airborne particles. Filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters at controlling most airborne indoor particles."
The EPA goes on to say that "medium efficiency air filters are generally less expensive than HEPA filters, and allow quieter HVAC fan operation and higher airflow rates than HEPA filters since they have less airflow resistance."
HEPA (High Efficiency Particulate Air) filters are the top-of-the-line air filters. Most homes are not capable of having whole-house HEPA filtration systems installed without extensive modification. Therefore, the EPA's recommendation of filters with a MERV rating from 7 to 13 is something that potential customers should keep in mind.
The National Air Filtration Association gives a roughly similar answer. The highest range it recommends for residential systems is 9-12; higher numbers are said to be suited for hospitals or commercial buildings rather than homes.
To put this into perspective…typical HVAC filters are in the MERV 1-4 range. Frankly, most do not even advertise their rating as they remove very little from the air delivered to the home.
