Air filters are a must-have for every homeowner. Why? Indoor air quality is vital – and every HVAC system today requires constant air filter replacement. Both air quality and system efficiency depend on clean and unclogged filters. 

Every air filter on the market has a MERV rating. What is MERV?  And how can you determine the best MERV value for your home and how important is it?

Here’s a breakdown below on MERV ratings for air filters!


MERV = Minimum Efficiency Reporting Values

What is a MERV rating? MERV is an acronym for Minimum Efficiency Reporting Values. The MERV rating is a measure of a filter’s capacity to contain and stop airborne particles that are between 0.3 and 10 microns in size. This includes pollen, dust mites and mold spores. It can also include microbiology such as bacteria cells and viruses.

A MERV rating ranges between 1 to 20. Large particles, such as dust mites or balls of pollen, are stopped by lower MERV ratings. Higher MERV ratings can stop particles of a smaller size, such as viruses and bacteria.


The MERV Rating Table

  • MERV 1 to MERV 4.
    • Filters 3-10 Microns @ 20% Efficiency
  • MERV 6
    • Filters 3-10 Microns at 50% Efficiency
  • MERV 8
    • Filters 3-10 Microns with 85% Efficiency
  • MERV 10
    • Filters from 1-3 microns with 50% to 65% efficiency
    • Filters 3-10 microns 85% plus efficiency
  • MERV 12
    • Filters from 1-3 microns with 80%-90% efficiency
    • Filters 3-10 microns at 90% plus efficiency
  • MERV 14
    • Filters from 0.3 to 1 microns with 75% to 85% efficiency
    • Filters 1-3 microns at 90% plus efficiency
  • MERV 16
    • Filters 0.3-1 microns at 75% plus efficiency

Efficiency and Microns

What does a MERV rating actually mean? The number of microns indicates how small of particles can be stopped by the filter. The percentage indicates the likelihood that those particles will be stopped. At 50% efficiency, MERV 6 can stop particles between 3-10 microns in size. The filter will capture approximately half of the particles within this range. To remove all particles within this range, it will take the filter several times.

MERV 10 filters particles 3-10 microns at 85% efficiency and can stop smaller particles at approximately 50% efficiency. With each pass, 85% of larger particles are stopped and half of the smaller particles are stopped.


What MERV Rating Do You Need for Your Home?

Many people use MERV 1-4 filters to remove dust, dander and carpet fibers, and prevent dust buildup inside their homes. MERV ratings 8-12 can provide a better level of air quality and a lower cost than higher rated filters. They filter smaller particles in the air and increase the percentage of large particles that are removed with each pass.

You should consider the health and cleanliness of your home as well as dust-generating sources. If there are any sick people or additional sources of dust such as pets, you can increase your MERV rating to improve air filtration.

Which MERV-rated HVAC filter is best for replacement? It all depends upon the needs of your home.

American Air Repair can be reached at (813) 802-2183 if you are interested in more information or have concerns about the air quality in your home.