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Serving The Greater Fresno Area Since 1970

Serving The Greater Fresno Area Since 1970


Donald P. Dick Air Conditioning Blog

Shopping For A MERV Filter: So What Do All Those Numbers Mean, Anyway?

If you have been shopping for a new air filter for your HVAC system, you may have noticed that the filters each come with a MERV number of between 1 and 20. But what do those numbers mean, anyway?

Well, MERV is a rating system for air filters. It rates how well the filter cleans the air of microscopic pollutants, such as germs, mold and dust. The acronym stands for Minimum Efficiency Reporting Value, which is not quite as complicated as it sounds:

  • “Minimum” simply means that the filter is guaranteed to work at least as well as its rating indicates, if not better. This is because the filters are tested in worst-case conditions.
  • “Efficiency” refers to the percentage of microscopic pollutants that the filter catches with each pass; if it catches a high percentage, it is more efficient at doing its job.
  • “Reporting Value” indicates that it is the reported value from an actual test.

A filter with a MERV of 1 is pretty much useless for cleaning the air of microscopic particles; such filters are designed for larger pieces of dust and debris, but not for bacteria or viruses. A rating of 20, on the other hand, indicates the filter would remove nearly 100 percent of all pollutants with a single pass, no matter how small the particles are.

Most San Joaquin Valley HVAC systems are not designed for use with ultra-high MERV filters, however. These filters have such tiny gaps for air to pass through that they decreasing the system’s air flow, reducing the efficiency of your air conditioner or furnace and costing you more on your energy bills. HVAC professionals can redesign your system to better handle these filters, but for most homes, a filter with a MERV of between 7 and 13 is ideal. Such filters do not significantly impact air flow, but can still provide good indoor air quality.

For an expert opinion on which air filter will work best in your San Joaquin Valley home, contact us at Donald P. Dick Air Conditioning in Fresno. We’ll be happy to answer your questions, and help your family breathe easier.

Our goal is to help educate our customers 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.

Donald P Dick Air Conditioning services the greater Fresno area in California. Visit our website to see our special offers and get started today!      

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