Frequently Asked Questions

Minimum Efficiency Reporting Value (MERV) is defined by ASHRAE Standard 52.2. MERV is the standard method to measure particulate filter performance. This single pass test measures particle counts in size ranges from 0.3 to 10 micron. The particles counts are then put into three groups: 0.3-1.0 micron; 1.0-3.0 micron; and 3.0 to 10 microns. (Click for Table)

Dust holding or dust holding capacity (DHC) is one of several performance metrics from ASHRAE Standard 52.2 testing. It is defined as the total weight of the standard test dust captured by the air cleaner over all of the dust loading steps.

MERV or Minimum Efficiency Reporting Value is defined by ASHRAE Standard 52.2 and includes MERV ratings from 1 to 16. There are no MERV ratings above 16. HEPA is not included in the MERV ratings and is defined by a separate standard.