MERV RATINGS
MERV stands for Minimum Efficiency Reporting Value. The rating is derived from a test method developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). Use the MERV rating as a comparison tool for evaluating the effectiveness of air filters. The higher the MERV rating the better the filter is at trapping specific types of particles. However, the MERV rating is not intended to be the sole basis for deciding which filter to buy, just as the horsepower of a car engine is not the only criteria in buying a car.