MERV stands for Minimum Efficiency Reporting Value. What does this mean to you though? MERV is a stardard ratings system set up by ASHRAE, the American Society of Heating, Refrigerating and Air-Conditioning Engineers. MERV is a way of comparing the effifiency of air filters without having to look at all the technical details provided by manufacturers. The higher the MERV rating, the more efficient the filter.
One important thing to keep in mind when comparing MERV ratings is that many companies DO NOT actually test their filters according to ASHRAE standards. They often come up with the number by testing larger particulate matter. Most common filters that you will see with a high MERV rating have NEVER been formally tested to verify this MERV rating.
Camfil FARR prides itself on the fact that all of it's filters have been tested using the ASHRAE Standard 52.1-1992.
- FARR 30/30 filters are rated at MERV 8
- Aeropleat III filters are rated at MERV 8
- Aeropleat IV filters are rated at MERV 8
- AP-eleven filters are rated at MERV 11
Camfill-Farr filters are "all mechanical" rather than electrostatic. They maintain consistent, high removal efficiency throughout the filter's life. Other companies' filters are made with electrostatically charged media, which loses efficiency over time.