About MERV Ratings
There are three ratings systems for air filters that are the most common used.
- MERV - "Minimum Efficiency Reporting Value" (Industry Standard Method)
- FPR - "Filter Performance Rating"
- MPR - "Microparticle Performance Rating"
MERV
MERV is an acronym for “Minimum Efficiency Reporting Value". This is the industry standard by which air filters are rated and is the only rating system that is regulated at the national level. It is the measure of how efficient a filter is at removing particles of different sizes from the air that passes through it. The MERV scale was established by ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers) in 1987 to measure air filter effectiveness on a more granular scale than other rating systems.
The MERV scale ranges from 1-16, designating how effective an air filter is at removing particulates of varying sizes. The higher the MERV rating not only indicated how much of a specific size particle it can capture and at what efficiency, but also the size of the particles it can capture. For example, a MERV 8 filter can capture up to 20% of particulates in the 1.0-3.0 micron range and up to 70% of particulates in the 3.0-10.0 micron range. Alternatively, a MERV 11 filter can capture up to 65% in the 1.0-3.0 range, up to 85% in the 3.0-10.0 range but can also capture up to 20% in the tiny, 0.3-1.0 range where MERV 8 captures none.
FPR
FPR is and acronym for "Filter Performance Rating" and was designed by Home Depot for air filters that are sold in their stores including Honeywell. FPR is based on a color coded scale from 4-10 to designate the quality and effectiveness of an air filter to capture different particles. FPR is similar to MERV in how it is calculated but not nearly as specific or accurate.