The Quick, Easy Guide to Answer All of Your Questions

August 20, 2021


You know it’s important to change the air filter in your home regularly, but how do you know what’s best for you?  With so many options and different rating systems, how do you make sense of it all to make the best choice for you and your family?  In this article, we look to simplify the rating systems for you, so you can pick the right filter for your home. 

What is MERV?

MERV is an acronym for Minimum Efficiency Reporting Value.  The MERV rating scale was developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) to measure the overall performance of an air filter.  MERV ratings are assigned to filters based on their ability to capture a variety of airborne particles.  These airborne particles range from large micron particles (ex. Pollen, dust, mold spores) down to smaller sub-micron particles (ex. Smog, tobacco smoke, dust mite debris).  The MERV rating is assigned to a filter only after it has been tested to the ASHRAE test standard.  The ASHRAE standard test is designed to measure the effectiveness of the air filter at capturing and removing a specific range and amounts of contaminants in the air.  From a consumer point of view, MERV ratings are very easy to understand.  The higher the MERV rating, the better the filter in terms of level of filtration.  Currently, ASHRAE test standards and the MERV rating scale are the accepted industry standard for rating an air filters performance.  For reference, we have included a chart to show the filter capabilities of air filters ranging from a MERV 1 to MERV 16. 


What is FPR?

The Filter Performance Rating System (FPR) is a proprietary rating system that was created by The Home Depot to measure the ability of an air filter to capture large particles, small particles, and the amount of weight gained caused by the filtration process over the life of the filter, or more simply put – weight gain.  This rating system is only used on air filters that are carried by The Home Depot, whereas the MERV scale is used on all air filters.  Just like with MERV ratings, the higher the FPR rating, the better the filter.  However, there are 2 important factors to keep in mind:

The FPR rating system and tests are not industry standard, only MERV ratings and tests are.
FPR ratings and MERV ratings do not match.  The FPR scale ranges from 1 to 10, while the MERV scale ranges from 1 to 20.

What is MPR?

Micro-particle Performance Rating (MPR) is a proprietary air filter rating scale developed by  The 3M Company to rate the performance of air filters.  Similar to the FPR rating system you read about previously, the MPR rating system and tests are not an accepted industry standard.  Compared to the MERV testing and FPR testing standard, the MPR tests place emphasis on the filters ability to capture smaller particles as opposed to the more common larger particles.  


We understand that the world of air filters can be confusing.  Not only are there multiple brands and sizes to choose from, but also multiple rating systems to try and compare.  Hopefully this helps give you a little better understanding of the rating systems, so your decision making can be stress-free.

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