Air filter efficiency refers to how well the filter can trap and hold airborne particles and contaminants such as dust, pollen, pet dander, and even microorganisms as they travel with the air flowing through your HVAC system. Air filter efficiency is of prime importance to HVAC system function and indoor air quality. Keep the following efficiency terms in mind and you’ll be able to find filters that will keep your system working and your air clean.

  • Initial and sustained efficiency: The initial efficiency of an air filter shows its ability to capture and retain particles when new. Sustained efficiency is how well the filter works over time.
  • Arrestance: Arrestance describes how well a filter traps and holds dust particles. It is determined by controlled laboratory testing.
  • Pressure drop or filter resistance: Pressure drop indicates the effect the filter has on air flow within the HVAC system. A furnace or air conditioner needs unobstructed and ongoing airflow to work correctly. A filter with a high pressure drop may restrict airflow too much, causing reductions in system effectiveness or even damage to equipment.
  • Dust holding efficiency: This rating describes how much dust the filter can hold at a particular pressure drop. More efficient filters can hold more dust.
  • MERV: Minimum efficiency reporting value, or MERV, is a common measure of basic filter efficiency. MERV indicates how well a filter traps and retains particles from 0.3 to 10 microns in size. You can find standard filters with MERV numbers from 1 to 16, with higher MERV ratings meaning better efficiency. HEPA (high-efficiency particulate air) filters are extremely effective, with MERV ratings from 17 to 20, but they are not often used in residential settings. Be cautious if using higher-MERV filters. They may restrict system airflow so much that they compromise heating and cooling and damage your HVAC equipment. Your trusted HVAC technician can advise you on what filter is best for your particular system and situation.

With a combined 120 years of experience in heating, air conditioning, and plumbing, Comfort Systems is a leading source of superior HVAC services for commercial and residential customers in the Wichita area. Contact us today for more information on air filter efficiency and for help choosing a filter that will work best for your HVAC system.

Our goal is to help educate our customers in Wichita, Kansas about energy and home comfort issues (specific to HVAC systems).  For more information about air filter efficiency and other HVAC topics, download our free Home Comfort Resource guide.