# MERV rating explained, and why MPR and FPR cannot be converted to it: what ASHRAE 52.2 measures, and what the 3M and retailer scales do not tell you

> MERV comes from ASHRAE 52.2 tests of 0.3 to 10 um particles in three ranges; MPR is 3M's 0.3 to 1 um scale; FPR has no standard. No conversion exists.

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| Source | https://ownerspec.com/air/guides/merv-rating-explained-mpr-fpr/ |
| Publisher | OwnerSpec (https://ownerspec.com/) |
| Published | 2026-10-02 |
| Updated | 2026-10-02 |
| Facts verified | 2026-10-02 |
| Disclosure | Contains affiliate links. OwnerSpec may earn a commission at no cost to the reader. |

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## Short answer

MERV, the Minimum Efficiency Reporting Value, is the only furnace filter rating defined by a
published standard. ANSI/ASHRAE Standard 52.2 counts particles from 0.3 to 10 micrometres
upstream and downstream of the filter and scores it from MERV 1 to MERV 16 on its minimum
capture in three size ranges: E1 is 0.3 to 1.0 um, E2 is 1.0 to 3.0 um and E3 is 3.0 to 10 um.
A MERV 13 must capture at least 50% of E1, 85% of E2 and 90% of E3 particles; a MERV 8 needs
20% of E2 and 70% of E3 and has no E1 requirement. MPR is 3M's own scale for Filtrete
filters and measures only 0.3 to 1 um particles; FPR has no published standard. No
standard converts either one to MERV. EPA says to choose at least MERV 13, or as high as
the system fan and filter slot can accommodate, and to ask an HVAC technician if unsure.

## Fact sheet

- **Answer:** MERV is the only one of the three ratings defined by a standard: ANSI/ASHRAE 52.2 scores a filter 1 to 16 on minimum capture of 0.3 to 1.0, 1.0 to 3.0 and 3.0 to 10 um particles. MPR is 3M's own 0.3 to 1 um scale, and FPR has no published standard behind it. No standard converts between them; 3M prints MPR 1900 beside MERV 13 on its own chart.
- **Basis:** ANSI/ASHRAE Standard 52.2-2017, Table 10-2 (E1, E2, E3 particle size ranges) and Table 12-1 (minimum composite efficiency per MERV), published by ASHRAE; EPA's MERV page for the 0.3 to 10 um range and the MERV 13 recommendation; 3M's own MPR vs MERV chart for the MPR pairings.
- **Assumptions:** Residential 1 to 5 inch pleated filters in a forced-air furnace or air handler; the MERV table is the 2017 edition of ASHRAE 52.2, the edition whose full text was readable.; FPR's owner, scale and weighting are not printed here: no source OwnerSpec could open on 2 October 2026 defines FPR (homedepot.com returned 403 and Access Denied); Filterbuy prints FPR equivalents beside its own MERV ratings, which is the only FPR figure cited.; Whether a given furnace tolerates a MERV 13 is the furnace maker's call: ASHRAE, EPA, Trane and Carrier all say to check the system, and none prints a cutoff.
- **Method:** OwnerSpec read ASHRAE 52.2-2017 from the ASHRAE-hosted PDF, EPA's two MERV pages, ASHRAE's filtration FAQ, Trane's and Carrier's MERV pages and 3M's MPR vs MERV PDF on 2 October 2026, and compared only the figures those documents print. This is a document comparison: no filter was tested, and no capture figure comes from anywhere but the cited source.
- **Primary source:** [ANSI/ASHRAE Standard 52.2-2017, Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size (ASHRAE-hosted PDF)](https://www.ashrae.org/File%20Library/Technical%20Resources/COVID-19/52_2_2017_COVID-19_20200401.pdf) (manufacturer or vendor document)
- **Facts verified:** 2026-10-02
- **Last updated:** 2026-10-02
- **Canonical URL (cite this):** https://ownerspec.com/air/guides/merv-rating-explained-mpr-fpr/

If you want one number that ranks a Filtrete MPR 1900 against an FPR 10 against a MERV 11 from a third brand, leave now: no such number exists in any source cited here.

## What does each scale measure?

Three ratings, three publishers, one standard. Only the MERV compares across brands,
because only the MERV has a published test method behind it.

| Scale | Who defines it | Range printed by the publisher | What it is tested against |
|---|---|---|---|
| MERV | ASHRAE, in ANSI/ASHRAE Standard 52.2 | 1 to 16 (EPA lists HEPA above the scale) | Minimum capture of 0.3 to 10 um particles in three ranges, E1 0.3 to 1.0, E2 1.0 to 3.0, E3 3.0 to 10 um, at the manufacturer's stated airflow |
| MPR | 3M, for its Filtrete filters | 300 to 2800 on 3M's own chart | 3M's PDF: the filter's ability to capture particles between 0.3 and 1 micron |
| FPR | No published standard in any source cited here | Not printed here: homedepot.com returned 403 on 2 October 2026 | Not printed here, same reason; Filterbuy lists MERV 11 as comparable with FPR 7 |

ASHRAE 52.2-2017 section 12.5 says the term MERV may appear in a performance report or on
product labelling only if the entire test procedure in the standard has been run. The
standard also tests the filter as it loads with dust, not only when clean: section 12.2 sets
the final test resistance at no less than twice the initial resistance.

MPR, the Microparticle Performance Rating, is 3M's description of its own product. The 3M
MPR vs MERV PDF states that MPR indicates a filter's ability to capture particles between
0.3 and 1 micron, which is the E1 range alone.

FPR, the Filter Performance Rating, has no published standard in any source OwnerSpec could
open. Home Depot's buying guide and product pages returned 403 to every request on 2 October
2026, so this page cannot say who defines FPR, what its range is or how it is weighted. Filterbuy
prints its MERV 11 filter as comparable with MPR 1000/1200 and FPR 7: a seller's pairing, not a conversion.

## What does ASHRAE 52.2 actually require at each MERV?

Each MERV is a floor, not a score. Table 12-1 of ASHRAE 52.2-2017 gives the minimum
composite efficiency a filter must reach in each size range to carry that number.

| MERV (ASHRAE 52.2-2017, Table 12-1) | E1, 0.3 to 1.0 um | E2, 1.0 to 3.0 um | E3, 3.0 to 10 um |
|---|---|---|---|
| MERV 5 | no requirement | no requirement | at least 20% |
| MERV 8 | no requirement | at least 20% | at least 70% |
| MERV 11 | at least 20% | at least 65% | at least 85% |
| MERV 12 | at least 35% | at least 80% | at least 90% |
| MERV 13 | at least 50% | at least 85% | at least 90% |
| MERV 14 | at least 75% | at least 90% | at least 95% |
| MERV 16 | at least 95% | at least 95% | at least 95% |

Two details matter when reading a box. The MERV is tied to a test airflow: section 12.4 of
the standard writes the designator as the MERV plus the airflow it was tested at, with
MERV 10 at 1970 cfm as the standard's own example. And MERV 1 to 4 filters, which capture
under 20% of E3 particles, are reported by arrestance from a dust-loading test instead.

## Which MPR does 3M print next to which MERV?

Only the pairings 3M itself prints, from its MPR vs MERV PDF. 3M prints its own minimum
capture rates for E1, E2 and E3 beside the ASHRAE minimum for the paired MERV, and the 3M
figures are higher than the floor in every row. Two MPR values share MERV 11, two share
MERV 13 and two share MERV 14, which is why the scales cannot be converted one to one.

| 3M MPR | 3M's minimum capture, E1 / E2 / E3 | MERV 3M pairs it with | Where to buy the 20x25x1 |
|---|---|---|---|
| MPR 300 | 12% / 38% / 34% | MERV 5 | Filtrete MPR 300, 6 pack |
| MPR 600 | 23% / 54% / 55% | MERV 7 | not linked |
| MPR 1000 | 41% / 77% / 88% | MERV 11 | Filtrete MPR 1000, 2 pack |
| MPR 1200 Odor | 43% / 78% / 88% | MERV 11 | not linked |
| MPR 1500 | 54% / 83% / 90% | MERV 12 | Filtrete MPR 1500, 2 pack |
| MPR 1900 | 62% / 87% / 95% | MERV 13 | Filtrete MPR 1900, 2 pack |
| MPR 2200 | 69% / 90% / 96% | MERV 13 | not linked |
| MPR 2500 | 77% / 93% / 97% | MERV 14 | not linked |
| MPR 2800 | 81% / 94% / 97% | MERV 14 | Filtrete MPR 2800, 2 pack |

Filtrete also sells an MPR 700 that retailer listings label MERV 8. The 3M chart has no
MPR 700 row, so that pairing is a listing title and not a 3M publication, and it stays out
of the table. A brand that prints MERV alone, such as the
Amazon Basics MERV 11, needs no translation.

## Does a higher MERV restrict airflow?

It can, and no source gives a number for when. EPA's wording is the honest one: at least
MERV 13, or as high as your system fan and filter slot can accommodate.

ASHRAE's filtration FAQ states that increasing filter efficiency generally leads to increased
pressure drop, which can reduce airflow, increase fan energy use, or both, and that if a
MERV 13 cannot be accommodated, the highest MERV the system accepts is the answer. EPA's air
cleaner guide says most furnaces and HVAC systems can accommodate a MERV 13 without equipment
problems provided the filter is replaced frequently, and to consult an HVAC technician to be
certain.

The furnace makers say the same without a cutoff. Trane: not every system can handle a
MERV 13 filter, as they can restrict airflow and affect system performance. Carrier: higher
MERV filters are denser and can restrict airflow, so consult the system's manual or a
professional to ensure the blower motor can handle the increased resistance.

The variable none of them can know is your furnace. EPA's condition for a MERV 13, that the
filter is replaced frequently, is the one you control, and the
[filter change interval guide](/air/guides/how-often-change-furnace-filter/) covers how often
that is. ASHRAE's filtration page adds that the filter must be sealed in its slot:
air that bypasses the frame is unfiltered whatever the MERV.

**Before you buy by the biggest number**

Read the furnace manual's filter line first, then measure the slot: the
[nominal vs actual size page](/air/parts/furnace-filter-sizes-nominal-vs-actual/) explains
why a "20x25x1" is not 20 by 25 inches. If the manual allows MERV 13 and the slot seals, the
[MERV 8, 11 and 13 furnace filter review](/air/reviews/best-furnace-filter-merv-8-11-13/)
compares the published figures. If the manual names a lower rating, a MERV 13 is the wrong
purchase however good the chart looks.

## What should you do first?

1. Find the filter line in the furnace or air handler manual and note the highest MERV it allows, or the words it uses if it names none.
2. Measure the actual slot depth: a 1 inch slot limits you to 1 inch filters whatever the MERV.
3. On a Filtrete box, read the MERV printed beside the MPR and ignore the MPR when comparing with another brand.
4. On a filter labelled with FPR, compare the MERV printed beside it; if no MERV is printed, the FPR alone cannot be checked against a standard.
5. Mark the install date on the frame and follow the [change interval guide](/air/guides/how-often-change-furnace-filter/), shorter for a denser filter.

## The picks

- **Filtrete MPR 1900, MERV 13, 20x25x1 (2 pack)**: Furnace manual allows a MERV 13 and the slot is 1 inch (3M MPR vs MERV chart: MPR 1900 minimum capture E1 62%, E2 87%, E3 95%, paired with MERV 13 (ASHRAE 52.2-2017 minimum E1 50%, E2 85%, E3 90%)) Amazon: https://www.amazon.com/dp/B00TUDHC0O/?tag=ownerspec-20
- **Filtrete MPR 1500, MERV 12, 20x25x1 (2 pack)**: Wants most of the MERV 13 figures with one step less filter density (3M MPR vs MERV chart: MPR 1500 minimum capture E1 54%, E2 83%, E3 90%, paired with MERV 12 (minimum E1 35%, E2 80%, E3 90%)) Amazon: https://www.amazon.com/dp/B00TUDHVO6/?tag=ownerspec-20
- **Filtrete MPR 1000, MERV 11, 20x25x1 (2 pack)**: Manual or technician says the blower should not see a MERV 13 (3M MPR vs MERV chart: MPR 1000 minimum capture E1 41%, E2 77%, E3 88%, paired with MERV 11 (minimum E1 20%, E2 65%, E3 85%)) Amazon: https://www.amazon.com/dp/B004Q69HIU/?tag=ownerspec-20
- **Filtrete MPR 2800, MERV 14, 20x25x1 (2 pack)**: Has a written OK from the furnace maker for the densest 1 inch Filtrete (3M MPR vs MERV chart: MPR 2800 minimum capture E1 81%, E2 94%, E3 97%, paired with MERV 14 (minimum E1 75%, E2 90%, E3 95%)) Amazon: https://www.amazon.com/dp/B00TUDHMDQ/?tag=ownerspec-20
- **Filtrete MPR 300, MERV 5, 20x25x1 (6 pack)**: Old furnace whose manual names only a basic fibreglass or low-MERV filter (3M MPR vs MERV chart: MPR 300 minimum capture E1 12%, E2 38%, E3 34%, paired with MERV 5 (ASHRAE minimum E3 20%, no E1 or E2 requirement)) Amazon: https://www.amazon.com/dp/B07FNXPGLG/?tag=ownerspec-20
- **Amazon Basics MERV 11, 20x25x1 (6 pack)**: Wants a MERV figure only, with no second scale to translate (Listing title prints MERV 11 and an actual size of 19.75 x 24.75 x 0.75 in; no MPR or FPR; ASHRAE 52.2-2017 MERV 11 minimum E1 20%, E2 65%, E3 85%) Amazon: https://www.amazon.com/dp/B088BYSCJ4/?tag=ownerspec-20

## Frequently asked questions

### Is MPR 1900 the same as MERV 13?

Only in the sense that 3M prints them side by side on its own chart. The 3M MPR vs MERV PDF pairs MPR 1900 with MERV 13 and lists a minimum capture of 62% for 0.3 to 1 um particles against the 50% a MERV 13 needs under ASHRAE 52.2-2017. MPR 2200 is also paired with MERV 13, so one MERV covers two MPR values.

### Is there an official FPR to MERV conversion chart?

None of the sources cited here publishes one, and ASHRAE 52.2 defines only MERV. The only FPR pairings OwnerSpec could read are a seller's own: Filterbuy lists its MERV 11 filter as comparable with FPR 7. Home Depot's buying guide could not be opened on 2 October 2026, so this page prints no FPR range or weighting, and you should compare the MERV on the label.

### What MERV rating does the EPA recommend for a home furnace?

EPA's MERV page says to choose a filter with at least a MERV 13 rating, or as high a rating as your system fan and filter slot can accommodate, and that you may need an HVAC technician to find the highest-efficiency filter that works for your system. EPA's air cleaner guide adds that most systems can take a MERV 13 if the filter is replaced frequently.

### Will a MERV 13 filter restrict airflow on my furnace?

It can on some systems, and nobody publishes a universal cutoff. ASHRAE's filtration FAQ says higher filter efficiency generally increases pressure drop, which can reduce airflow or raise fan energy use. Trane says not every system can handle a MERV 13, and Carrier says to consult the system's manual or a professional about the blower motor. Check the manual first.

### Why does a MERV 8 filter have no rating for the smallest particles?

Because ASHRAE 52.2-2017 Table 12-1 sets no E1 minimum below MERV 11. MERV 8 needs at least 20% capture in the 1.0 to 3.0 um range and 70% in the 3.0 to 10 um range, and nothing in the 0.3 to 1.0 um range. The E1 requirement begins at MERV 11 with 20% and rises to 95% at MERV 16.


## Sources

- [ANSI/ASHRAE Standard 52.2-2017, Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size (ASHRAE-hosted PDF)](https://www.ashrae.org/File%20Library/Technical%20Resources/COVID-19/52_2_2017_COVID-19_20200401.pdf) (manufacturer or vendor document)
- [EPA, What is a MERV rating?](https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating) (government or regulatory source)
- [EPA, Guide to Air Cleaners in the Home](https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home) (government or regulatory source)
- [ASHRAE, Filtration and Disinfection FAQ (PDF)](https://www.ashrae.org/file%20library/technical%20resources/covid-19/filtration-and-disinfection-faq.pdf) (manufacturer or vendor document)
- [ASHRAE, Filtration and Disinfection technical resources](https://www.ashrae.org/technical-resources/filtration-disinfection) (manufacturer or vendor document)
- [3M Filtrete, MPR vs MERV chart (PDF)](https://multimedia.3m.com/mws/media/1740587O/filtrete-merv-vs-mpr.pdf) (manufacturer or vendor document)
- [Trane, MERV 8 vs MERV 11 vs MERV 13](https://www.trane.com/residential/en/resources/blog/merv-8-vs-merv-11-vs-merv-13/) (manufacturer or vendor document)
- [Filterbuy, 20x25x1 MERV 11 pleated air filter](https://filterbuy.com/air-filters/20x25x1/merv-11/) (manufacturer or vendor document)
- [Carrier, What Is a MERV Rating?](https://www.carrier.com/us/en/residential/hvac-resources/what-is-merv-rating/) (manufacturer or vendor document)

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Citation: OwnerSpec, "MERV rating explained, and why MPR and FPR cannot be converted to it: what ASHRAE 52.2 measures, and what the 3M and retailer scales do not tell you", https://ownerspec.com/air/guides/merv-rating-explained-mpr-fpr/, facts verified 2 October 2026.
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