HEPA Filtration -- How It Works to Provide Optimal Indoor Air QualityYou’d be surprised at what’s floating around in your Indianapolis home’s air. The average home is host to a wide variety of airborne contaminants ranging from dust and pet dander to mold spores, bacteria, viruses and even volatile organic compounds (VOCs). Many of these contaminants act as triggers for asthma, allergies and other respiratory problems. While an ordinary air filter does an effective job trapping airborne particles, “High Efficiency Particulate Air” or HEPA filtration goes further in making your home’s indoor air cleaner and healthier.

HEPA filters have been around since the 1940s and commercially available since the 1950s. These filters have a Minimum Efficiency Reporting Value (MERV) of 17-20, at the top of the scale, signifying their superior performance to most conventional filters. HEPA filtration is common for commercial and industrial uses, although the average residential HVAC system can benefit with some modification.

The average HEPA filter relies on three distinct methods for capturing airborne particles as small as 0.1 micron:

  • Interception: Particles above 0.4 microns are intercepted by larger fibers after coming in close contact with them.
  • Impaction: Particles above 0.4 microns that attempt to pass through the filter are swept into and embedded within a fiber.
  • Diffusion: Particles below 0.1 micron collide with other molecules and bounce around the filter until they collide with a fiber.

According to the Environmental Protection Agency, true HEPA filters with a MERV of 17-20 offer a minimum efficiency between 99.97 percent and 99.99 percent for removing particles as small as 0.3 microns. While HEPA filtration offers plenty of benefits, there are a few caveats:

  • Ordinary filters with a MERV of 7-13 offer similar performance to HEPA filters with less noise, lower cost and much less airflow resistance.
  • HEPA filtration only targets airborne particles. These filters must be combined with an activated carbon filter to target gaseous pollution.
  • HEPA filters must be professionally installed in most residential HVAC systems, further adding to their cost and complexity. However, they are available as the filtration component of some stand-alone air cleaners.

To learn more about how HEPA filtration can improve your Indianapolis home’s indoor air quality, please contact us at Mowery Heating, Cooling and Plumbing.

Our goal is to help educate our customers in Brownsburg, Indiana and surrounding areas about energy and home comfort issues (specific to HVAC systems). 

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