What Is HEPA Filter

What Is HEPA Filter

When you hear the term “HEPA” air filters, most people are left scratching their heads. We are told that these type of appliances are a “good choice” when shopping for an air purifier, but how can we besure if we aren’t clear on what they actually are? Here is a beginner’s guide to understanding HEPA filtration and the many benefits it offers for air purification in your home and beyond.

HEPA filters, or high efficiency particulate filters, are a type of air filter which satisfies specific efficiency standards set by the United States Department of Energy. HEPA filtration technology is made up of randomly arranged fibers and it provides the filtration of much smaller particles than the traditional vacuum filters. Made of fiberglass, the fibers used often have diameters of 0.5 to 2.0micrometers. The diameter of the fiber, the filter thickness and face velocity effects how HEPA filters work. HEPA filtration systems are crucial to suppressing the increase of airborne germs.


The particles that are caught in a HEPA filter go through a sequence of three components, known as interception, interaction and diffusion.With the interception apparatus, particles follow a line in an air stream. Impaction is where the larger particles cannot avoid escape of the fibers and are forced to sink in the fibers. The diffusion function is the outcome of a collision with the gas molecules of smaller particles that are caught in the filters path.

HEPA Filter Uses

HEPA filter systems have been implemented into multiple types of transportation methods, such as cars, planes and trains. Only recent car models have had the HEPA technology implemented into their air systems. Home vacuum cleaners have recently been equipped with HEPA filtration technology. The system works with vacuum cleaners to absorb polluted air through the filter, while no air gets by the filter. This is referred to in the vacuum industry as “Sealed HEPA” or “True HEPA.” Perhaps the industry that most commonly benefits from this is the airline industry. Through the use of HEPA technology, the spread of airborne bacteria is lowered in planes. The air filtration systems used in airliners are compared to those applied in surgical clean rooms. Essentially the idea is to remove the bacteria and germs while reusing the air.

Due to the increasing concern of indoor air pollution, many companies have rushed to make a profit without the proper knowledge of airpurification. These companies end up leaving customers with filters that use the HEPA name but aren’t manufactured with the customer in mind. However, there a many suppliers that do provide affordable and quality HEPA systems. When you are making your purchase, it pays to be picky.

Out of 10,000 particles that pass through a high quality HEPA filtration system, the maximum of the 3 particles will enter the air system. The longer HEPA systems operate the more effective they become. Some filters use a ultra-violet light to kill living germs and viruses trapped in the filter. Most high quality filters are rated 99.995% in value by the Department of Energy.

Shelly Thomas is a contributing writer for AirPurifierGuide.org, a site that helps consumers make the best decision when it comes to choosing a HEPA air purifier system. One of the most popular lines available are the iqair air purifiers .