Understanding MERV Ratings

MERV stands for Minimum Efficiency Rating Value. This is an industry standard rating system that allows you to compare filters made by different manufacturers. A MERV rating is a numerical value ranging from 1 (lowest efficiency) to 20 (highest efficiency) and indicates how well the filter captures and holds dirt and dust of a specified size range. The chart below shows the MERV ratings, corresponding particle size ranges, and efficiency level as measured by the percentage of particles captured. 

The MERV air filter efficiency rating system was developed by the ASHRAE, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers.

We recommend using a MERV 8, or higher, filter for nearly all HVAC applications. For better filtration, you may consider MERV 11 or 13. Many LEED Certified buildings require MERV 13 ratings. We have access to several manufacturers of MERV 11 and MERV 13 filters in Cedar Rapids and the surrounding areas.