Hansberger Refrigeration Blog: Your AC Repair Resource

Air Filter Shopping? Why The Highest MERV Rating Isn’t Always The Best Choice

If you’re looking for an air filter for your heating and cooling equipment, chances are you’re looking for one that offers the best possible filtration. The Minimum Efficiency Reporting Value (MERV) is used throughout the HVAC industry to rate air filters; it may point you toward the highest-rated filter available, but it won’t tell the whole story about that product or how effectively it will perform over the long haul.Air Filter Shopping? Why The Highest MERV Rating Isn't Always The Best Choice

It might be helpful to view MERV as less of a rating and more of a way to help homeowners choose air filters based on their ability to trap the smallest airborne particles – such common materials as dander, dust, pollen and pet hair. MERV numbers usually correspond to a filter’s effectiveness at trapping particles at various micron sizes in standardized tests. For instance, an air filter rated at MERV 8 supposedly can trap over 70 percent of airborne particles between 3 and 10 microns in size. Meanwhile, a MERV 16 filter – the highest available for residential use – can trap 95 percent of particles at sizes ranging from 0.30 microns to 10 microns.

Nevertheless, air filters with the highest MERV rating aren’t always the best choice for plenty of reasons:

  • Filters with dense filtration media feature more restrictive airflow, especially as the media becomes embedded with airborne pollutants. Restrictive airflow also slows down recirculation, which impacts home comfort and indoor air quality.
  • A lack of proper airflow not only places greater strain on HVAC equipment, but it can cause components like condensers and blower fans to wear out prematurely.
  • Some high-rated filters are electrostatically enhanced to capture more particles. Electrostatic degradation can cause these filters to become less effective over time.

In many cases, a MERV 8 filter can be far more effective in providing clean, comfortable air than a comparable MERV 11 filter. However, it’s up to you to choose the best air filter that meets your home’s comfort and air quality needs, as well as working well with your HVAC equipment.

If you want more information on MERV and how it relates to air filters, please contact us at Hansberger Refrigeration & Electric Company. For more than 60 years, we’ve provided the best air conditioning, refrigeration and electrical services for residents of the Yuma area.

Our goal is to help educate our customers in Yuma, Arizona 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 Resource guide.

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