“Too Many MERV’s” ?? According to ASHRAE and IEST – 20 Possible Assignable MERV’s Three “Markets” E3 Arrestance MERV 1-4 General Equipment E2 Middle Efficiency MERV 5-12 Equipment and People E1 High Efficiency MERV 13-20 Marginalized Health People and Specialized End Uses Real Differences Between the Markets Arrestance High Efficiency Real Differences Within These Markets MERV 5 MERV12 Difficulties Variety of End Uses Variety of Air Handling Types Variety of Pollutants