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.
Here is the one number to look for when you buy a furnace filter: MERV, the ANSI/ASHRAE 52.2 rating every lab measures the same way, so you can compare any brand against any other. You can largely ignore the big numbers on the box - MPR (a 3M-only scale) and FPR (Home Depot's scale) are marketing ratings each seller controls. They do not translate cleanly to MERV, and the same proprietary number can even point to a different MERV depending on how thick the filter is. The table below shows you, for every furnace filter we score, the true MERV next to the proprietary number the brand leads with - and whether it buries the real rating behind it. We confirmed every MERV here against the manufacturer's own published source.
What the catalog shows
- 8 of 11 scored furnace filters print their true MERV plainly with no proprietary scale layered on top - the kind of label that lets you compare like for like.
- 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
Use the mappings below to translate the box number back into a real MERV. They come from 3M's own MPR-to-MERV chart and Home Depot's FPR chart, and they are approximate - the proprietary scales were never standardized. The catch most conversion charts gloss over is that the same proprietary number can land on a different MERV depending on 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
Worst offenders first: filters that hide the true MERV behind a proprietary scale lead, then those that do print MERV but still headline an MPR or 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 actually does its job.
| 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 work in a brand's favor precisely because they do not let you compare across brands - a higher MPR sells you one 3M filter over another 3M filter, but tells you nothing about the Honeywell sitting next to it on the shelf. 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 that dimension. One more thing worth your attention: a cheap filter you swap every quarter can cost you more over a year than deeper media you replace once, which is why we put the annual-cost column right here. 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/