FPR vs. MERV vs. MPR: What’s the Difference Between Air Filter Ratings?

When you’re shopping for air filters, it’s easy to get overwhelmed by the sheer number of options. Not only do you need to choose the right size, type, and thickness, but you also have to pick the right efficiency rating. And to complicate things even further, there are multiple rating systems to measure air filter efficiency—including FPR, MERV, and MPR. Below, we’ll focus on the differences between FPR versus MERV versus MPR to help you pick the best filter rating for your household.

What Are the Differences Between FPR, MERV, and MPR?

FPR, MERV, and MPR are three different air filter rating systems. Each was developed by a different organization or company, but they all measure the same thing: how effectively an air filter blocks out particles of varying sizes. In all of these systems, a higher rating equals better particle filtration.

Here’s a quick rundown of each rating system: 

• Filter Performance Rating (FPR): This system uses a rating scale of 1–12 to categorize the effectiveness of filters sold at Home Depot.

• Minimum Efficiency Reporting Value (MERV): MERV ratings are the industry standard for measuring air filter effectiveness. The rating scale goes from 1–20.

• Microparticle Performance Rating (MPR): This rating system describes how well 3M filters capture microparticles. The scale ranges from 300–2,800.

FPR vs. MERV vs. MPR: Differences in Use and Origin

One of the main differences between the three systems is where they’re used: 

• FPR: Home Depot created these ratings to help customers easily understand the particle-blocking capabilities of the filters it sells. However, the company also lists MERV ratings on its filters.

• MERV: Established by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) in 1987, the MERV system is the industry standard for measuring a filter’s effectiveness. No matter where you buy your air filters, they should include a MERV rating.

• MPR: 3M developed this system to rate how effectively its filters block particles smaller than one micron (like smoke and smog). Its products also have MERV ratings.

Rating Scale Differences

Aside from their origins and uses, the other key difference between MERV versus FPR versus MPR systems is their rating scales and what each number actually indicates as far as effectiveness. 

FPR

Home Depot’s FPR ratings range from 1 to 12, with higher ratings equating to better particle filtration. Here’s what some of the most common ratings can block: 

• 5 (Good): Dust mite debris, pet dander, pollen, dust, and lint

• 7 (Better): All of the above, plus mold spores and bacteria

• 9 (Best): All of the above, plus particles in coughs and sneezes, most smoke, and allergens

• 10 (Premium): All of the above, plus odors and smog particles

• 12: (Ultimate): All of the above, plus virus and volatile organic compound (VOC) particulates

MERV

MERV’s scale goes from 1 to 20. Filters with MERV ratings of 17 or higher are known as high-efficiency particulate air (HEPA) filters and can block at least 99.97% of airborne particles. Here’s what other common MERV ratings can block: 

• 1 to 4: Extremely large particles

• 5 to 6: All of the above, plus large dust particles

• 7 to 9: All of the above, plus lint and finer dust

• 10 to 12: All of the above, plus pet dander, smoke, pollen, and mold spores

• 13 to 17: All of the above, plus bacteria and particles from sneezing

• 17+: All of the above, plus viruses and carbon dust

MPR

The MPR system has the widest rating scale, ranging from 300 to 2,800. Its filters can block:

• 600: Lint, household dust, dust mite debris, mold spores, and pollen

• 800: All of the above, plus pet dander

• 1,000: All of the above, plus smog particles

• 1,200: All of the above, plus particles in coughs and sneezes

• 1,500: All of the above, plus bacteria and viruses

• 1,600: All of the above, plus candle soot

• 2,200: All of the above, plus exhaust particles and fine particles under 2.5 micrometers in diameter (PM2.5)

Particle-Blocking Effectiveness Differences

Even though they use different scales, all three rating systems measure the same thing. Under each system, you’ll find a range of products with various particle-blocking effectiveness levels, meaning that no single system is better than the others in terms of filtration capability.

Tips for Picking the Right Air Filter Rating

Because there are multiple filter rating systems (and many ratings within each system), choosing the right air filter rating isn’t always easy. In reality, the best filter rating will depend on a few factors, including your family’s needs and your budget. 

This chart can help you determine the right option for your household:

Still unsure which filter rating is best for you? A local AC installer can point you in the right direction.