Understanding MPR and MERV

MPR (Microparticle Performance Rating) and MERV (Minimum Efficiency Reporting Value) both measure how well a filter works, but they do things differently. 3M created the MPR rating to include microscopic particles not visible to the naked eye, something the MERV scale doesn’t measure.

MPR (Microparticle Performance Rating)

Scientists at 3M believe that MERV only tells part of the story. It’s why we created a different measurement — Microparticle Performance Rating (MPR). This rating includes microscopic particles not visible to the naked eye. Microparticles (Size E1 and E2) are not even measured on the MERV scale until it reaches MERV 11.

Filtrete™ Brand technology makes it possible to capture the tiniest particles – between 0.3 and 1 micron in size — including bacteria and viruses through select high-performing filters within the portfolio.

MERV (Minimum Efficiency Reporting Value)

Minimum Efficiency Reporting Value (MERV) is the industry standard for measuring how well a heating and cooling system’s filter captures particles. MERV air filter ratings range from 1 (least efficient captureability) to 16 (very efficient).

Many homes use filters with a MERV rating of 1-4 which mostly filter out dust, lint and pollen among other larger, common particles — they do very little to trap small microparticles.

Understanding Particle Sizes

There are 3 particle-size groupings for MERV and MPR – E1, E2, and E3. Smaller particles, E1 being the smallest, can be captured in the lungs.

E1 = 0.3 – 1 µm
Includes bacteria, virus, candle soot, PM 2.5, and exhaust particles.

E2 = 1 – 3 µm
Includes smoke, smog, cough and sneeze particles, and pet dander.

E3 = 3 – 10 µm
Includes lint, dust, mold spores, pollen and pet dander.

E1 = 0.3 – 1 µm
Includes bacteria, virus, candle soot, PM 2.5, and exhaust particles.

E2 = 1 – 3 µm
Includes smoke, smog, cough and sneeze particles, and pet dander.

E3 = 3 – 10 µm
Includes lint, dust, mold spores, pollen and pet dander.