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Serving The Greater Fresno Area Since 1970

Serving The Greater Fresno Area Since 1970


Donald P. Dick Air Conditioning Blog

Air Filter Ratings: What Do They Mean?

Air Filter Ratings: What Do They Mean?Changing your air filter every one to three months is a simple and effective way to extend the life of your HVAC system and encourage a clean indoor environment. Learn how to choose the right kind of filter to keep your system working properly and your indoor air healthy.

When you’re shopping for your air filter, take note of the MERV rating. This number will help you understand the quality of filtration the filter can provide by measuring the kind of particles the filter will trap.

  • Low-Efficiency: With a MERV rating between 1 and 4, these filters provide the most minimal filtration available. They will catch the largest particles that measure 10 microns or more in size, such as dust mites and textile fibers. These filters won’t have a great impact on indoor air quality; they mostly serve to prevent build-up of particles on the fans and coils in your HVAC equipment.
  • Mid-Efficiency: For improved air quality in your home, and to control indoor allergens, select an air filter with a MERV rating between 5 and 13. These filters will catch particles 3 to 10 microns in size, such as mold spores and pet dander, providing the highest quality filtration appropriate for residential use.
  • High-Efficiency: Filters with a MERV rating from 14-16 are only appropriate for commercial use. The most efficient filters available, HEPA filters, are rated from 17-20. These filters will restrict airflow in a typical residential unit, requiring professional upgrades to the system if they are to be used. These high-efficiency air filters are used in environments which must be very clean, such as hospitals or laboratories.

The best air filter for the typical home has a rating between 7 and 12. This middle ground on the MERV rating chart will provide filtration of allergens such as pet dander or dust mites while allowing appropriate airflow for the typical residential HVAC system.

If you have any questions about improving air quality and comfort in your Fresno home, contact Donald P Dick Air Conditioning. We have been providing superior service to the greater Fresno area for nearly 40 years.

Our goal is to help educate our customers in the greater Fresno, California area about energy and home comfort issues (specific to HVAC systems).  For more information about air filter ratings and other HVAC topics, download our free Home Comfort Resource guide.

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