MERV Ratings

What's a MERV...?

Minimum Efficiency Reporting Value (MERV) is the established air filter industry rating that measures the effectiveness of air filters based on the ASHRAE rating.  The higher the MERV rating, the finer the filtration, meaning fewer dust particles and other airborne contaminants that can pass through the filter.

For example, a MERV-13 filter has to catch 90% of particles in the 1-10 µm ranges and 75% of particles in the .3-1 µm range.

Understanding Microns

A single strand of the finest human hair is approximately 20 micrometers, or microns, in diameter. If you would slice that strand in half and then slice one
of those halves in half...and then one more time, you are left with a strand that is 2.5 microns in diameter. As you can see in the chart below, there are three different ratings depending on the micron size and as you learned above, those particles are extremely tiny. The average human eye cannot see particles smaller than 50-60 microns (µm).

It is recommended to change your filters every three months to ensure proper filtration and to keep contaminates controlled throughout your facility. Let Nelson-Jameson help determine the best filter for your application. Call our filtration specialists today.