MERV vs FPR vs MPR Air Filter Ratings

MERV vs FPR vs MPR air filter ratings, which is better? What’s the difference between these air filter ratings? Conversations around air filter ratings tend to create more of confusion and less of clarity.

I put together this resource to clear the air. Hopefully, this post clarifies the difference for you and helps you make informed air filter purchase decisions.

MERV vs FPR vs MPR Filter Ratings

A MERV rating measures a filter media’s ability to remove particles in the 0.3-10 micrometer range while MPR measures the ability to capture particles smaller than 1 micrometer. Actually, the MPR scale focuses on particle sizes that the MERV scale “ignores” until MERV 10.

As for the FPR rating, it’s a simple system used by Home Depot to rate various products promoted by different manufacturers such as Honeywell. There’s no reliable way to covert between these filter rating systems. However, each rating system is reliable enough.

What is a MERV Air Filter Rating?

A MERV rating is a numeric value ranging between 1 and 20 and describes a filter’s ability to remove air pollutants of a particular size distribution. The American Society of Heating, Refrigeration, and Air Conditioning Engineers developed this filter performance rating system in 1987. This number represents the worst-case air filtration performance of a filter when removing air contaminants in a particular size distribution.

For example, if an air filter has a stated MERV rating of between 1 and 4, it can remove pollen, dust mites, textile fibers, carpet fibers, and sanding dust down to the 10-micron particle size.

In this resource, I explain in everyday language the MERV rating meaning if you’re interested. I’ve also included a MERV rating chart so you can learn what air filters in a given MERV range can do and what they can’t do.

What is a Good MERV Rating?

All MERV ratings are good. That said, the higher the MERV rating, the more granular the air filtration. While higher-rated filters are highly efficient at removing the finest particles, they restrict airflow immensely. As a result, they aren’t as energy-saving as lower-MERV options.

Lower-MERV air filters such as MERV 1 through 4 aren’t great at capturing extremely tiny filters. However, these filters are good enough at removing larger particulates. And they do the job without overly limiting airflow.

For most households, a MERV rating of 8-10 should be good enough. The best rating is MERV 13 provided that your HVAC system can operate without problems when you install this high-grade filter. Unfortunately, MERV 13 filters have been found to over-strain certain HVAC systems.

What is an FPR Air Filter Rating?

FPR is an abbreviation for Filter Performance Rating. Like MERV, the FPR rating describes a filter media’s air cleaning ability. But unlike the MERV rating which starts at 1 and ends at 20, the FPR scale ranges from 4 to 10. Home Depot developed this rating, and while it’s different than MERV, it’s pretty similar to it.

Both MERV and FPR use numerical values to communicate filter effectiveness. However, the FPR ratings relies correspond to a one of 4 colors in a color-coded system. These colors are green, red, purple, and black.

FPR Filter Rating Chart

FPR Filter RatingColor Code Identifying the RatingMeaning of Color CodeWhat’s Removed?
4 to 5GreenGoodLarge particles including dust, lint, dust mites,pet dander, and pollen
6 to 7RedBetterSmall particles and larger particles ranging from dust, dust mites, mold spores, pet dander, pollen, and bacteria.
8 to 9Purple/VioletBestLarge particles and small particles as captured by 6-7-rated filters but also filter out smoke, smog, viruses, and microscopic allergens
10BlackPremiumEverything removed by filters rated 10 on the FPR scale, but also filter out odors

What is a Good FPR Rating?

Any filter with a rating of 4-5 on the FPR scale should be good enough for removing common household air pollutants including dust, lint, dust mites, pet dander, and pollen.

What is an MPR Air Filter Rating?

MPR stands for Microparticle Performance Rating. Developed by 3M, the MPR filter rating measures the ability of an filter to remove sub-micron particulate matter. The MPR rating scale uses much higher values compared to MERV. It starts from 300 to 2200 versus 1 to 20 for MERV.

The higher the MPR value, the better the filter media is at capturing indoor air contaminants smaller than 1 micron in diameter. This rating system measures a filter’s effectiveness at tackling particles in the 0.3-1-micron range. It actually offers more comprehensive filtration compared to MERV rating. Here’s a startling fact: MERV doesn’t start measuring sub-micron particulates until MERV 10!

Is an MPR Rating of 300 Good Enough?

An MPR value of 300 is the lowest MPR rating a filter can have. Filters made to this standard remove household dust and lint well and nothing much besides.

A rating of 300 MPR is similar to a MERV rating of 5 and FPR of less than 4. Evidently, it’s a pretty lame rating and won’t do enough for a person who reacts to allergens such mold spores and pollen. An MPR of 1000+ is where serious filtration starts happening.

Below is…

An MPR Rating Chart

MPR rating chart
Image Credit: HVAC Training Shop

What is a Good MPR Rating?

If it’s just dust, a low MPR rating of 300 should suffice. But if you’re looking to capture a whole bunch of contaminants ranging from dust, mold spores, pollen, pet dander, smoke, bacteria, viruses, and even car exhaust fume particles, you need the best-rated filter.

You need a filter with a rating of not less than 2200. With such a filter, you shouldn’t worry about most PM2.5 particles and PM10 particulates.

MERVvs FPR vs MPR Ratings Chart

These three filter ratings are somewhat different. But they’re similar in that they measure the same phenomenon, a filter’s ability to reduce indoor air pollution.

Unfortunately, there’s no way to accurately convert any of the ratings to the other two. That said, the chart below should help you estimate how each rating relates to the other two. *This isn’t an air filter rating conversion chart.

FPR Filter RatingMERV RatingMPR Rating
4 to 56 to 8~600
6 to 78 to 11~600 to ~1000
8 to 911~1000
Note: ~ means approximately

*Treat the chart above as indicative rather than definitive.

Wrapping Up on HVAC Filter Ratings

While the MERV, MPR, and FPR ratings aren’t exactly the same thing, they measure the same quality: a filter’s capacity to capture contaminants.

Each of them was developed by trustworthy and knowledgeable entities. And all are reliable as far as comparing the effectiveness of air filters.

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