What Is a HEPA Filter?

Posted: January 16, 2023

The Gold Standard for Removing Airborne Particles

One of the most effective products used to improve indoor air quality today is the high-efficiency particulate air (HEPA) filter.

HEPA filters, which are considered the gold standard for removing airborne particles like dust, pollen and bacteria, are highly recommended for anyone who suffers from allergies or respiratory ailments like asthma. These highly effective air filters are used in air purifiers and forced-air HVAC systems like furnaces and central air conditioning units.

According to the U.S. Environmental Protection Agency, a HEPA filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any other airborne particles with a microscopic size of 0.3 microns.

These are known as “true HEPA filters,” which must meet strict industry standards for air filtration. The difference between a HEPA filter and a regular air filter is that HEPA filters are composed of thousands of thin fibers. This design is much more effective than the porous material—such as cotton and polyester—that is used to manufacture standard, less inexpensive air filters.

There are also “HEPA-type filters” available, but these are less effective, with a 99% efficiency rate of capturing particles of 2 microns or more.

What HEPA filters can’t do is remove odors and some types of volatile organic compounds (VOCs). You can solve this by installing a HEPA air purifier that has additional filters built in, such as a carbon filter.

HEPA Filters and COVID-19

Interest in air purifiers with HEPA filters skyrocketed after COVID-19 entered our lives. According to the CDC, COVID-19 particles on their own measure only about 0.1 microns in size. That’s too small for a HEPA filter to trap. But fortunately for us, when COVID-19 particles travel through the air, they attach themselves to the larger respiratory droplets released when an infected person coughs or sneezes. A HEPA filter can trap these larger droplets, including those tiny—and sometimes deadly–COVID-19 particles.

HEPA Filters: A Short History

Like many modern inventions, HEPA filters sprang from scientific research during World War II.

During that time, scientists were racing against time to develop the first atomic bomb. While this work progressed, it became critical to protect scientists from exposure to radioactive air particles. Thus, the introduction of the HEPA filter.

After the war, HEPA filters began being used in medical, commercial, and residential settings. As an example, hospitals use HEPA filters to help stop the spread of airborne germs. You can also find HEPA filters not only in residential air purification and air cleaning systems but some vacuum cleaners too. Read more history as well as a complete guide to HEPA filters.

Changing Your HEPA Filter

As you might expect, because HEPA filters are so effective at trapping air particles, they tend to become clogged more quickly than standard, less effective filters. While the recommended replacement rate varies—depending on where these filters are used and the number of particles they trap—HEPA filters typically need to be changed more often than standard filters. Some HEPA filters can be cleaned to extend their life. Please consult your owner’s manual for specifics.

As an industry leader in the installation and service of indoor air quality products, you can trust the experts at Wilson Oil and Propane to keep the air in your home clean and healthy. Read more about the indoor air quality solutions we offer.