23 1/2 x 23 1/2 x 1 Filtrete Micro Allergen Reduction Filter - #9840
(case of 6 Filters)
23 1/2" X 23 1/2" X 1" Filtrete® Micro Allergen Reduction Filter from 3M - #9840 - 6 pack
The Filtrete® Micro Allergen Reduction Filter carries a 3M Microparticle Performance Rating (MPR) of 1000 - roughly equivalent to a MERV 11 rating
Click here for detailed comparison of 3M Filtrete® 1" Filters
WHY USE MPR RATHER THAN MERV RATING?
The Heating, Ventilating and Air Conditioning (HVAC) industry uses the ASHRAE 52.2 Standard, which assigns a Minimum Efficiency Reporting Value (MERV) to a filter. One part of MERV reports a filter's ability to capture medium to large particles between 1 and 10 microns. This value is helpful in comparing the performance of different filters but it is not adequate alone because particles greater than one micron make up only about 1% of the contaminants in your indoor air.
Another part of MERV addresses submicron particles. 3M calls this the MPR or Microparticle Performance Rating. It measures a filter's ability to capture particles between 0.3 and 1.0 micron. Based on independent laboratory tests, 3M's MPR measures a filter's ability to capture submicron particles that make up 99% of the particles in the air, such as bacteria, smoke and smog.