What's with the different Air Filter rating guidelines such as MERV, FPR, MPR?

There are 3 commonly known air filter rating guides, the standard industry rating is called MERV, and then Home Depot and Lowes use different rating systems known as FPR and MPR. 

The American Society of Heating, Refigeration, and Air-Conditioning Engineers ( ASHRAE ) designed a rating system known as Minimum Efficiency Reporting Value, commonly known as MERV rating.  MERV system ratings go from 1 - 20.

The filters sold in Home Depot use the  Air Filter Performance Rating (FPR) System.  The FPR system ranks filters on a 1-10 scale.

Filter manufacturer Filtrete created Microparticle Performance Rating ( MPR ), and their filters are sold in Lowes.  The MPR system ranks filters on a scale of 300 - 2200.

The higher the rating, the higher efficiency of the filter.

Here is an approximate comparison of the rating systems.

Hope this helps in your comparisons of air filter quality and performance.

Kind regards,

Ryan