Your air conditioner keeps you cool during the hot summer months. But did you know it can also improve your home’s air quality? 

Air conditioning filters remove harmful and smaller particles from your home, so you and your family can breathe easier. However, not all air filters are made equal. To assess their quality, a few different rating systems have been developed. 

This article will explain these rating systems in depth. In turn, you’ll be able get an air conditioning replacement service to help you choose an HVAC air filter with confidence. 

The Purpose of Air Filters

Air filters clean the air as it circulates through the HVAC system. They capture and remove harmful particulates before cool air re-enters your home. Depending on the quality of your filter, it traps the following particulates:

  • Lint
  • Dust
  • Dirt
  • Pollen
  • Mold
  • Dander
  • Wood 
  • Plaster
  • Bacteria
  • Viruses

Air Conditioning Filters Ratings

Air conditioning filter quality is based on the size of particulate matter that a filter can capture. Household particulate material is measured in microns. Thus, the smaller the micron filtration, the higher the filter quality. 

While high-quality filters are more expensive, they prevent a greater portion of harmful microorganisms from circulating through the air. 

Air Conditioning Filters Ratings Systems

There are a few different rating systems that assess the quality of air filters: 

  • Minimum Efficiency Reporting Value (MERV) – Developed by the Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the MERV system is the standard rating system used around the world. This system rates filters on a scale of 1 (the lowest-quality) to 16 (the highest-quality). 
  • Microparticulate Performance Rating (MPR) – The MPR rating system was developed by a group of scientists at 3M. MPR measures HVAC air filter quality based on the smallest of particulates. It’s then ranked on a sliding scale from 100 to 2800.
  • Filter Performance Rating (FPR) – The FPR system was developed by The Home Depot. Its rating scale goes from 4 to 10 and operates similar to MERV.

MERV Filter Ratings Explained

Since the MERV system is the industry standard, let’s examine its ratings:

  • MERV 1-4 – These filters provide the most basic filtration and are the cheapest on the market. They can only capture particulates that are 10 microns or larger, like pollen, dust, pet dander, and lint. Thus, they don’t clean the air very thoroughly. They also need to be switched out more frequently than higher-quality filters.
  • MERV 6-8 – These filters capture dust particles as small as 3 microns. They filter out everything that MERV 1-4 filters do, as well as mold spores, pet dander, hair spray, and dust mite contaminants. These filters are adequate for most homes. 
  • MERV 9-12 – These filters trap and hold dust particles as small as 1 micron. In turn, they prevent particulates like auto emissions, flour, humidifier dust, and lead dust from circulating through your home. As a result, they’re the recommended AC filter for homeowners with allergies, asthma, COPD, and other respiratory issues. 
  • MERV 13-16 – These are the highest quality MERV filters. They capture particles and contaminants as small as 0.3 microns, including bacteria, viruses, carbon dust, sneeze droplets, smoke, and insecticide spray. These filters are commonly found in hospitals and manufacturing facilities. Keep in mind that most home HVAC systems are not compatible with these filters unless they undergo special retrofitting. 

Filter Rating System Comparison

Here’s a key for comparing filter quality across rating systems:

  • MERV 8 is equivalent to MPR 600 and FPR 5
  • MERV 11 is equivalent to MPR 1000-1200 and FPR 7
  • MERV 13 is equivalent to MPR 1500-1900 and FPR 10

Air Conditioning Filtration Best Practices

To protect your HVAC system and your health, you should switch out your air filters frequently, at least every 2 to 3 months. You’ll know it’s time for a change if you can no longer see the filter material through the captured particulate. 

By changing out dirty filters, you’ll keep the air flowing through your HVAC system smoothly and enjoy these benefits:

  • Clean air
  • Reduced allergy and asthma triggers
  • Reduced mold and mildew growth
  • A lower energy bill

What Filter Should You Choose For Your Home? 

If you want clean air, you might be eager to outfit your HVAC system with the highest-quality air filter you can find. However, this isn’t always the best move. 

Even though highly-rated MERV filters are great for people with allergies and other sensitivities, they limit airflow within your HVAC system. In turn, they can reduce the effectiveness of your air conditioning unit, potentially resulting in costly AC failure. 

Check with your HVAC specialist before installing a new home air filter. They’ll know whether or not your air conditioning system can handle it. 

Improve Your Air Quality With Simpson Sheet Metal

If you have any questions about air conditioning filtration, reach out to the HVAC specialists at Simpson Sheet Metal. As experts in all things AC, they’ll be happy to help you with any air conditioning repair, installation, or maintenance request. They can also provide guidance on which home air filter is right for you and your home.  



EPA. Guide to Air Cleaners in the Home.

Filtrete. The Right Filter For You.