HEPA Air Purifier Reviews: A Comparison of HEPA Filters
Most popular HEPA air purifier reviews:
See how the HEPA air purifiers compare to the listing of top rated air purifiers.
A HEPA (High Efficiency Particulate Air) filter is a mechanical filter that traps airborne particles as they pass through an air purifier. A true HEPA filter is rated to remove 99.97% of all particles that are 0.3 microns in size or larger. A micron, also known as a micrometer is one millionth of a meter. As a reference point a human hair is approximately 60 microns in diameter and a grain of pollen is 5 microns. 90% of all airborne particles are less than 10 microns in size and the challenge with air purifiers is that most of these particles are too small to see. The light weight and low mass of these particles allow them to be suspended in the air for extended periods of time while the larger and heavier dust type particles tend to settle on the ground much more quickly.
In a review of air purifier technologies, HEPA air purifiers are the recommended filtration method of leading government agencies such as the American Lung Association, Department of Homeland Security and EPA. This favorable review is due to the high efficiency of the HEPA filter and it’s inherent ability to improve performance over time.
Recommendation: to best enjoy the benefits of cleaner air, find a purifier with a high efficiency filter, good air flow and reasonable noise level.
HEPA Air Filter Advantages
HEPA air filters are rated highly due to their ability to remove a very high percentage of particles with each pass of air through an air purifier. If you suffer from allergies or asthma a HEPA air purifier is almost always the best choice since its filtration is designed to remove the tiny particles that trigger an allergic reaction. The particle removal performance is generally significantly better with a HEPA filter as compared to the ionic and electronic air cleaners. In addition, HEPA air filters often improve performance over time whereas the filterless technologies (ionic, electrostatic) see a decrease in performance over time as the electronic plates become dirty.
A HEPA filter does not generate ozone although you will want to review the product specifications for the air purifier to verify there is not an elevated level of ozone from the electrical workings of the air purifier. We have not found any elevated levels of ozone in the HEPA air purifiers we have tested. In late 2010, the state of California will require all air purifiers to be at a safe ozone level and this will likely increase the percentage of air purifiers sold with the HEPA technology.
HEPA Air Filter Disadvantages
The primary downside to a HEPA air filter is the noise level associated with moving sufficient air through the HEPA filter for a given room. Noise level can be subjective and some users commented positively on the white noise effect but we also found some users that did not like the noise level on the higher fan speeds of a HEPA air purifier. Noise levels are measured in decibels (dB) and provide a good reference point when comparing HEPA air purifier models. Since the HEPA filter media is dense it generally requires more energy than an electronic type air cleaner and therefore generates various levels of white noise. Operating a HEPA air purifier on a lower fan speed will result in lower noise levels that can be silent however there is also a reduced air flow associated with the lower fan speed.