About HEPA Air Filtration

Research Studies and Facts

HEPA air filters are largely considered the most effective type of air filter for solid particles, such as dust and other allergens.

 

 

How HEPA Filters Work

HEPA air filters are made from very tiny glass fibers that are made into a tightly woven paper. This creates a filter consisting of a multitude of very small sieves that can capture extremely small particles, including some biological agents. Once trapped, contaminates and particles are not able to flow back into circulation, due to the highly absorbent pores of the HEPA air filter.

HEPA Air Filter Facts and Studies

  • HEPA air filters remove 99.97% of particles down to 0.3 microns in size, almost 300 times smaller than the width of a human hair.
  • HEPA air filters were developed by the Atomic Energy Commission during the second World War. They were originally designed to remove radio active dust from their plants.
  • HEPA air filters are recommended by the U.S. Dept. of Homeland Security.
  • Journal of Hygiene study found that ionizers increase efficiency of HEPA air filters. The Surround Air Multi-Tech air purifiers include an ionizer in addition to True HEPA filters.
  • A study by Air & Waste Management Association found the combination of a HEPA air filter and germicidal UV lamp reduced bacteria by 80% in a 3072 cubic foot chamber.
  • HEPA filters are recommended by the Mayo Clinic for allergy proofing the home.
  • In a study by the UK Lung Research Centre, HEPA air cleaners significantly reduced airborne cat allergen particles when the purifier was used with a cat in the room.
  • In a study by the Environmental Health Sciences Department at the University of Michigan, HEPA air purifiers reduced the level of fine particulate matter in the air (such as cigarette smoke), by 30-70%. The particulate level was measured in the room where the air purifier was running, and the fan speed was set to medium, since users often run their air purifiers at a lower level when they are in the room.

What to Look for in a HEPA Filter

  • Make sure it is a "True" HEPA filter, and not just "HEPA-like". All Surround Air purifiers include a True HEPA filter.
  • Make sure the HEPA air purifier comes with a germicidal UV lamp, otherwise, your HEPA filter could become a breeding ground for microbes with all the particulate it will capture. All Surround Air purifiers include a UV lamp as well.
  • Make sure the air purifier has strong air flow. Somewhere between 100 and 200 cfm is ideal. If it is lower than this, it will be effective for smaller spaces. If it is too high, it will be far too noisy to tolerate, while also consuming far too much electricity. Plus, if it is too high, it can push the air past the UV lamp too quickly to be properly disinfected.
  • Replacement costs. Know how much it will cost to replace the HEPA filter before you buy.
  • If possible, find a HEPA filter that comes with an ionizer. A Journal of Hygiene study found that negative ions increase the efficiency of HEPA filters. Almost every Surround Air purifier includes an ionizer.
  • Permanent or Cleanable versus Disposable. Most HEPA filters will last about a year before needing to be replaced. But there are permanent/cleanable HEPA filters designed to last the life of the unit. Ideally, even "permanent" HEPA filters should be replaced every 2-3 years, for optimal effectiveness. You may not get quite the same effectiveness as a HEPA that is replaced annually, but it will provide you the convenience and cost-savings of a longer-lasting filter. 
  • Pre-filter. Although not a necessity, a pre-filter can prolong the life of a HEPA filter.

About Other Air-Cleaning Technologies:

HEPA Air Filtration
Activated Carbon Filtration
Germicidal UV (Ultraviolet) Purification
Negative Ion Purification
Photocatalytic Oxidation