Air filters have a broad range of applications based on their MERV rating. MERV (Minimum Efficiency Reporting Value) ratings are determined by a filter’s ability to capture differently sized particles between 0.3 and 10 microns (µm). MERV ratings range from 1-20, where the lower ratings are associated with a larger particle size. When selecting a filter, it’s not always about the numbers! It is always important to use a filter rating that is appropriate for the system you’re using. If your system’s purpose is to help reduce the transmission of illnesses by reducing the concentration of illness causing particles, then your filter rating is going to be much different than if you were trying to reduce the amount of sandpaper dust in a machine shop. If a filter with a higher than recommended rating is used in a system, it will put additional strain on your HVAC system. This additional strain can negatively impact the system’s efficiency and performance.