The MERV rating scale shows the efficiency of a filter. That is, the percentage of particles removed based on the size of the particle.
Many air purifiers use a foam pre-filter and those fall in the MERV 1-4 range and are the lowest performing filters. A higher performance pre-filter will further improve the quality of the air. We recommend a MERV 6 to MERV 8 rated pre-filter to balance the filtration capabilities with less airflow resistance. Every air purifier offered from Oransi has a MERV Rating of 16-18.
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