The Difference Between FPR, MPR, and MERV Rating Systems

Published: September 13, 2024 Updated: August 7, 2025 Nick Kornblith 5 minute read

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Air Filter Rating Systems Overview

Trying to choose the right filter for your air purifier but don’t know where to start? No worries– understanding the various filter rating systems is the first step. The most common ratings systems are MERV, MPR, and FPR. Sounds like alphabet soup, right? Hang tight–we’ll break it all down. Each is used to measure air filter efficiency and each system evaluates filters differently, so at Alen, we’d like to help you understand what the ratings represent. You can then make informed decisions and take control of optimizing your indoor air quality.

Air Filter Rating Systems Overview

So what’s the alphabet soup about? Air filter rating systems allow us to better understand how well a filter can remove contaminants or pollutants from the air. These systems provide a standardized way to compare the effectiveness of different filters. Let's take a look at the rating systems you commonly see:

What is a MERV Rating?

Let’s start with the MERV–Minimum Efficiency Reporting Value rating. This system was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). The MERV rating ranges from 1 to 20 and measures a filter's ability to capture particles of varying sizes:

MERV 1-4: Captures large particles like pollen, dust mites, and textile fibers.
MERV 5-8: Better for capturing mold spores, hair spray, and cement dust.
MERV 9-12: Effective at capturing legionella, humidifier dust, and lead dust.
MERV 13-16: Captures bacteria, tobacco smoke and car emission particulates.
MERV 17-20: The highest ratings, often used in hospitals, can capture particles smaller than 0.3 microns, at a high efficiency level, including viruses.

ASHARE recommends a MERV 6 or higher and you’ll most commonly see people use a MERV 8 filter. However, the rating can differ based on the setting. For instance, a MERV 8 to MERV 13 can be best suited for residential settings while hospitals, for instance, might use a MERV 14 to MERV 20 as more efficiency is needed. Filters higher than MERV 14 are uncommon in residential use as they may be too restrictive for ordinary HVAC systems, although some newer homes have whole home HEPA systems that can use higher MERV rated filters without damaging the HVAC system.

What is an MPR Rating?

Another common rating is MPR–Micro-Particle Performance Rating––which is a system developed by 3M to rate their Filtrete brand filters. The MPR rating focuses specifically on the filter's ability to capture particles smaller than one micron, such as smoke, bacteria, and fine dust. Here’s the range:

MPR 300-600: Good for capturing larger particles like pollen and dust.
MPR 700-1000: Effective at capturing mold spores and dust mite debris.
MPR 1200-1500: Better at capturing small particles like smoke and smog.
MPR 1900-2800: Provides the highest level of filtration, capturing particles like bacteria and viruses.

This rating system is widely applied to assess many filters and provides a clear understanding of a filter’s ability to capture micro-particles and improve indoor air quality. An MPR of 1500-2800 is ideal.

What is an FPR Rating?

A third common rating is FPR–Filter Performance Rating–that was developed by Home Depot to provide a simpler way for consumers to compare filters. The FPR scale ranges from 1 to 12, with higher numbers indicating better filtration performance. What you need to know is that the FPR creates a weighted average for each filter for its ability to capture various sized particles:

FPR 4-5: Captures pollen, pet dander, and dust.
FPR 6-7: Effective at capturing smoke, smog, and mold spores.
FPR 8-9: Captures bacteria, smoke, and fine dust.
FPR 10: The highest rating, capturing the smallest particles like viruses and allergens.
FPR 12: Ultimate rating for the highest performing air filter including VOCs and virus particulates.

The FPR system is similar to the MERV system but includes a color-coding scheme to make it easier for consumers to understand. An FPR of 10, for example, is comparable to a MERV of 20. However, a FPR 1 doesn’t exactly equate to MERV 1 as MERV has a wider range and scale differences.

What is the Difference Between MERV, FPR, MPR, and HEPA Filters?

You should now be pretty familiarized with the MERV, FPR, and MPR rating systems. A key takeaway is that each system measures filter performance differently, but all are important measurements in determining the ability of your filter to function effectively. But there’s something else we want to compare with these rating systems and that’s High-Efficiency Particulate Air (HEPA) filters. HEPA filters work in concert with your HVAC filters. Since the HEPA filters are so effective at capturing particles, your HVAC filters will last longer–saving you money.

At Alen, our HEPA filters capture 99.9% of particles down to 0.1 micron. Alen HEPA filters are the equivalent of MERV 17 in terms of their efficiency. This exceptional efficiency makes HEPA filters the gold standard in air purification! It also highlights Alen’s goal to have you achieve superior air purification in your home.

Having an overall understanding of these ratings and the superior performance of HEPA filters can help you choose the best filter for your air purifier. Become the hero of your home, and purchase filters that enable you to optimize your air. To make your buying easy, Alen has an automated filter subscription service.

HEPA Filters and Alen Air Purifiers

At Alen, we use HEPA filters in all of our devices to provide you with the ultimate air purifying technology. HEPA filters are exceptional at capturing tiny particles from the air, making them equivalent to MERV 17. HEPA filters capture allergens, dust, mold, and bacteria, providing you with clean, fresh air. Alen’s beefier filters remove 99.9% of unwanted particles. Alenize your air with the air purifier that puts you in complete control of your indoor air quality!

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