Data · MPR/FPR is not MERV
MERV honesty
Of the 11 furnace filters we score, 0 lead with a proprietary MPR or FPR number without plainly disclosing the true ANSI/ASHRAE 52.2 MERV, and 3 market a proprietary rating at all. MPR and FPR are not MERV - the same proprietary number can map to a different MERV by filter depth.
A furnace filter has exactly one standardized rating: MERV, the ANSI/ASHRAE 52.2 scale every lab measures the same way. The big numbers on the box - MPR (a 3M-only scale) and FPR (Home Depot's scale) - are proprietary marketing ratings the seller controls. They are not interchangeable with MERV, and the same proprietary number can map to a different MERV by filter depth. This table shows, for every furnace filter we score, the true MERV next to the proprietary number it leads with - and whether the brand hides the real rating behind it. Every MERV here was confirmed against the manufacturer's own published source.
What the catalog shows
- 8 of 11 scored furnace filters label their true MERV plainly with no proprietary scale - the honest baseline.
- 3 market an MPR or FPR number, and 0 lead with that proprietary number without plainly disclosing the standardized MERV - the bait this site exists to flag.
- 9 of 11 have a MERV we confirmed against the manufacturer's own authoritative source (3M's MPR-to-MERV chart, the Honeywell/Home Depot FPR SKUs, and the Aprilaire and Lennox spec sheets).
The verified MPR / FPR to MERV conversion
The mappings below come from 3M's own MPR-to-MERV chart and Home Depot's FPR chart. They are approximate - the proprietary scales are not standardized - and the trap most conversion charts miss is that the same proprietary number can map to a different MERV by filter depth: FPR 10 is MERV 13 in a 1-inch panel but MERV 12 in 4-inch media. We score the true MERV either way.
MPR (3M Filtrete) to MERV
| MPR 600 | MERV 8 |
| MPR 1000 / 1085 / 1200 | MERV 11 |
| MPR 1500 / 1550 | MERV 12 |
| MPR 1900 / 2200 | MERV 13 |
FPR (Home Depot) to MERV
| FPR 4 | MERV 6-8 |
| FPR 7 | MERV 10-11 |
| FPR 9 | MERV 11-12 |
| FPR 10 | MERV 13 (1-inch) / MERV 12 (4-inch) |
Every scored furnace filter, by honesty
Sorted worst-first: filters that hide the true MERV behind a proprietary scale lead, then those that print MERV but still headline an MPR/FPR number, then the plain-MERV filters. We score the true MERV either way - the honesty column is about what the box tells you, not whether the filter works.
| Filter | Score | True MERV | Marketed as | Hides MERV | Annual cost |
|---|---|---|---|---|---|
| Honeywell Home Elite Allergen FPR 10 (1-inch)1" depth | 3.3 | MERV 13 | FPR 10 | no | $108.00/yr |
| 3M Filtrete MPR 1900 (Premium Allergen)1" depth | 3.9 | MERV 13 | MPR 1900 | no | $91.96/yr |
| 3M Filtrete MPR 1500 (Allergen)1" depth | 4.6 | MERV 12 | MPR 1500 | no | $73.96/yr |
| Flanders EZ-Flow II Fiberglass (throwaway)1" depth | 3.0 | MERV 1 | MERV (no proprietary scale) | no | $92.04/yr |
| Nordic Pure MERV 12 (1-inch)1" depth | 5.9 | MERV 12 | MERV (no proprietary scale) | no | $38.68/yr |
| Aerostar MERV 13 (1-inch)1" depth | 5.9 | MERV 13 | MERV (no proprietary scale) | no | $34.68/yr |
| Amazon Basics MERV 11 (1-inch)1" depth | 5.9 | MERV 11 | MERV (no proprietary scale) | no | $33.60/yr |
| Aprilaire 213 (4-inch media, MERV 13)4" depth | 6.0 | MERV 13 | MERV (no proprietary scale) | no | $64.99/yr |
| Aprilaire 413 (4-inch media, MERV 13)4" depth | 6.0 | MERV 13 | MERV (no proprietary scale) | no | $64.99/yr |
| Honeywell FC100A1037 (4-inch media, MERV 11)4" depth | 6.0 | MERV 11 | MERV (no proprietary scale) | no | $39.05/yr |
| Lennox Healthy Climate X6673 (5-inch media, MERV 11)5" depth | 6.0 | MERV 11 | MERV (no proprietary scale) | no | $35.98/yr |
How to read this
MERV is the only rating an independent lab measures the same way for every filter, so it is the only one we score. MPR and FPR are useful to a brand precisely because they are not comparable across brands - a higher MPR sells a 3M filter against another 3M filter, not against the Honeywell next to it. When a filter leads with the proprietary number and buries the MERV, our Rating Honesty score marks it down, and hiding the MERV entirely caps the dimension. A cheap per-filter price replaced every quarter can also cost more per year than deep media replaced once, which is why the annual-cost column is here too. See our guide on MERV vs MPR vs FPR for the full breakdown.
FAQ
- What MERV is MPR 1900?
- MPR 1900 is MERV 13 on the standardized ANSI/ASHRAE 52.2 scale. MPR is 3M's proprietary Filtrete scale; MERV is the only rating an independent lab measures the same way for every brand.
- What MERV is FPR 10?
- FPR 10 is MERV 13 in a 1-inch panel filter, but MERV 12 in 4-inch media. The same FPR number maps to a different MERV depending on filter depth, which is why FPR is not a reliable MERV substitute.
- Is MPR or FPR the same as MERV?
- No. MPR (3M) and FPR (Home Depot) are proprietary marketing scales each seller controls, and they are not comparable across brands. MERV (ANSI/ASHRAE 52.2) is the only standardized rating an independent lab measures the same way. We score the true MERV.
Cite this analysis
Figures are computed across every scored furnace filter and update as the catalog grows. Cite with attribution to FilterScored and a link to this page.
FilterScored. "MERV vs MPR vs FPR: Which Furnace Filters Hide the Real Rating." https://www.filterscored.com/reports/merv-honesty/