What Does Pressure Drop Mean for Cartridge Air Filters?

Pressure drop is defined as the difference in pressure between two points in a system, often measured at the inlet and outlet of a filter. It represents the resistance or loss encountered by the fluid (which can be air, water, or other liquids) as it flows through the filter media. In the context of cartridge filters, "pressure drop" refers to the reduction in air or fluid pressure as it passes through the filter cartridge. Essentially, it's a measure of the resistance that the filter introduces to the flow. The higher the resistance, the more energy it takes to move air through the system; a high filter drop makes the system work harder and use more energy to push air through the filters.

Pressure drop is often used as an indicator of filter loading; as filters become clogged with particulates, increased pressure drop will be noted across the filter. Other aspects that influence pressure drop include:

  • Filtration efficiency: Filters with a higher MERV rating, or a HEPA rating, will have a larger pressure drop across the filter and require more energy to push air through. 
  • Media Type: Different filter media (e.g., pleated, spun, melt-blown) offer varying levels of resistance.
  • Filter Design: The design of the cartridge, including the size, shape, pleat design, and density of the filter media, can influence pressure drop.
  • Flow Rate: A higher flow rate can result in a higher pressure drop because more air is trying to pass through the filter in a given time.


Get answers from an expert now.