Is There Really A Difference Between A True HEPA Filter And A HEPA-Like Filter?

The science has never been more clear. Clear air is essential to good health. Exposure to pollutants has been proven to cause a large range of health issues including lung disease, heart problems, impaired cognition, and even death. In fact, air pollution kills an estimated seven million people worldwide every year.

If you think that air quality is not an issue in your area, think again. The World Health Organization reports that 99% of people in the world breathe in air that exceeds their limits of pollution. 

Whether it’s harmful gases or dangerous particle matter, the importance of keeping your indoor air clean is obvious.  But, what type of purifier is best for your home?

HEPA filters are typically considered the safest and most effective purifiers for home use. In fact, the CDC even recommends using HEPA filters in hospitals and other buildings to help keep indoor air pollutant-free.  But, many purifiers use the word “HEPA” in their description and those classified as True HEPA filters can be a considerable financial investment. Is it really worth the money?

What are HEPA filters?

HEPA stands for High Efficiency Particulate Air. Modern HEPA filters are typically made of plastic or fiberglass, but that wasn’t always the case. 

In fact… the original HEPA filters were actually made from asbestos and cellulose fibers and were used to protect people from radioactive particles during the Manhattan Project, a classified government program to create the first nuclear weapons!

Once the basic technology was designed, The Army Chemical Corps used that same filtration paper in air purifiers to protect soldiers at army headquarters along the front line. 

While modern-HEPA filtrations have come a long way since these first designs, the same basic technology is still used. 

How do HEPA filters work?

Most modern HEPA filters consist of interlaced fiberglass or plastic fibers that are twisted into a maze that is designed to take particles out of air circulation. HEPA filters trap particles in different ways according to their size.

Particles larger than 1 micron: As air flows through the filter, the larger particles are heavy enough that the airflow from the filter propels them forward into the fibers of the filter where they get stuck.

Particles that are .3  to 1 micron: Particles this size can fit between the gaps in the filter. But, they are too heavy and slow to follow the airflow around the HEPA filter and end up getting stuck in the fibers.

Particles smaller than .3 microns: While HEPA filters only need to filter particles of .3 microns, they’re are also really good at filtering out smaller ones. Because of a phenomenon known as Brownian Motion, tiny particles bounce wildly off of other larger particles in the air in random patterns that send them careening off into different directions, causing them to hit the fibers of the HEPA filter and get stuck.

What’s the difference between a True HEPA filter and other HEPA-like filters?

A TRUE HEPA filter must be able to trap 99.97 percent of particles that are 0.3 microns. That .3 micron size is important because scientists have determined that particles of that size evade air filters more than larger or smaller particles. 

HEPA filters that don’t meet the standards often go by other names such as “HEPA-like” or “Ultra HEPA”.  While these filters may be made of the same materials as HEPA filters, the filters themselves are not manufactured in the same way and don’t go through the same rigorous testing as HEPA filters. 

Ok, but… won’t a HEPA-like filter do basically the same thing for less money?

Not necessarily! Most of these “HEPA like filters” are only able to filter out 99% of particles 2 microns or larger, compared to True HEPA filters which must be able to trap 99.97 percent of particles that are 0.3 microns. 

While that may not seem like a significant difference, it’s important to remember that the most harmful particles are the smallest ones. In fact, PM2.5 (inhalable particles, with diameters that are generally 2.5 micrometers and smaller) are responsible for 4.2 million premature deaths every year globally. 

True HEPA filters will remove PM2.5 from your indoor air.

What kind of filters do aeris purifiers use?

aeris purifiers all use True HEPA filters. Our aair 3-in-1 PRo and aair Lite are both rated HEPA H13, meaning that they are 99.95% effective at removing particles down to .1 microns. Our Medical Pro offers even greater protection. It’s rated HEPA H14, which means that it is 99.995% effective at removing particles down to .1 microns.

While True HEPA filters are excellent at trapping particulate matter, they are not able to remove harmful chemicals from your air. That’s why aeris purifiers have the added benefit of an activated carbon filter. With a combination of True HEPA and activated carbon filters, our purifiers will keep your indoor air free of particulate matter, gases, and odors.

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