Filter Efficiency Guide


The percentage of test dust, by weight, that a filter is able to capture



American Society of Heating, Refrigeration and Air Conditioning Engineers


ASHRAE 52.1 Standard - Test standard for HVAC filters that measures arrestance, dust spot efficiency and dust holding capacity

ASHRAE 52.2 Standard - Test standard that measures the fractional particle size efficiency (PSE) of an HVAC filter and assigns a MERV depending on the PSE in three different particle size ranges


Minimum Efficiency Reporting Value (MERV)

A numerical system for comparing filters based on the particle size efficiency. A MERV 1 is least efficient and MERV 16 is the most efficient.


Particle Size Efficiency (PSE)

The filter's ability to remove airborne particles in specific size ranges from 0.30 to 10.0 microns in diameter, using controlled aerosol consisting of potassium chloride (KCI)