HEPA Filters: Your Solution for Cleaner Air

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In this blog, we will dive into the world of HEPA filters, exploring their functionality, benefits, and practical uses.

What’s HEPA Filter?

HEPA Filter


A HEPA Filter is a type of high-efficiency air filter that is specifically made to collect tiny particles in the air. Usually composed of fiberglass or synthetic materials, these filters are built with a densely woven mesh of fibers. Air may flow through the complex structure, but particles as small as 0.3 microns are trapped, along with smoke, pollen, dust, and allergies.  A human hair's diameter is around 70 microns, for comparison.


What do HEPA Filters Remove?

HEPA filters excel at capturing a wide range of airborne contaminants, including:

  • Microscopic Particles: Particles in the microscopic size range include smoke, dust, and aerosols with a diameter of only 0.3 microns.
  • Allergens: Allergens include dust mite detritus, pollen, mold spores, and pet dander.
  • Aerosolized Bacteria and Viruses: HEPA filters may capture a sizable portion of the bacteria and viruses in the air, while not being 100% reliable.


Who Invented HEPA Filters?

HEPA filters originated during World War II.  To safeguard personnel from dangerous airborne particles during nuclear research, scientists at the United States' Manhattan Project required a solution. The result was the development of highly efficient filters that could collect extremely small radioactive particles.  This technique was modified for civilian usage following the war, which resulted in the widespread use of HEPA filters that exist today.


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Why HEPA Filter is Used?

HEPA filters offer a multitude of benefits, and here are some:

  • Better Indoor Air Quality: HEPA filters considerably raise the standard of indoor air by removing a variety of airborne pollutants. For those who have allergies or asthma and are sensitive to dust, pollen, and other allergens, this is very beneficial.
  • Reduced Allergens: Pet dander, mold spores, and dust mite debris are among the major allergens that HEPA filters efficiently catch, making homes for allergy sufferers more pleasant.
  • Enhanced Protection from Respiratory Issues: HEPA filters can help lessen exposure to germs and viruses in the air, which may help minimize the risk of respiratory ailments.
  • Improved Building Efficiency: A facility with cleaner air may have more energy-efficient HVAC systems and use less energy overall.


How HEPA Filters Work?

HEPA filters employ a three-pronged approach to air filtration:

  • Interception: As air passes through the filter, larger particles strike and stick to the filter strands.
  • Impaction: Heavy particles impact with and adhere to the fibers of the filter due to inertia when air undergoes abrupt turns inside its pleated structure.
  • Diffusion: The tiniest particles move randomly, brushing against and getting trapped by the filter threads.

The Minimum Efficiency Reporting Value (MERV) of a HEPA filter indicates how effective the filter is.  For HEPA filters to be certified, they need to receive a MERV value of 17 or above.  Greater efficiency in catching even tinier particles is indicated by higher MERV ratings.


How HEPA Filters are Made?

HEPA filters are constructed from a fine mesh of fibers, typically made from:

  • Fiberglass: The most often used material for HEPA filters, fiberglass is both economical and efficient.
  • Synthetic Materials: Certain HEPA filters are made of synthetic materials, such as polyester or polypropylene, which operate similarly to fiberglass and may even have hypoallergenic advantages.

After that, the filter medium is pleated to enhance its surface area and improve air filtration effectiveness.  In an air purifier, the filter media is encircled by a frame that gives it support and stability.


Can HEPA Filters be Cleaned and Reused?

Unlike disposable filters, some HEPA filters can be cleaned and reused.  However, the reusability depends on the specific model:

  • Traditional HEPA Filters: These filters should be changed every six months to two years, as directed by the manufacturer. They are normally disposable. Washing them can deteriorate the sensitive fibers and reduce their efficacy.
  • Washable HEPA Filters: A few HEPA filters have a washable design. The manufacturer's recommendations should always be followed for the right manner to clean. 

In general, it is advised to give them a gentle wash in cool water and to let them air dry entirely. Even HEPA filters that are washable eventually need to be changed because of their limited lifespan.


How Long do HEPA Filters Last?

The lifespan of a HEPA filter  depends  on several factors, including:

  • Filter Quality: Higher-grade HEPA filters tend to live longer than their less-priced counterparts because they are usually constructed of sturdier and more durable materials.
  • Usage: HEPA filters need to be changed more frequently and will clog more quickly in high-pollution situations.
  • Maintenance: Washable HEPA filters can have their lifespan extended by following the manufacturer's cleaning recommendations regularly.

Here's a general guideline for HEPA filter replacement:

  • Disposable HEPA filters: six months to two years, based on quality and usage
  • Washable HEPA filters: 1-2 years (as long as they are properly maintained and cleaned)


When are HEPA Filters Used?

HEPA filters are employed in a wide range of applications where clean air is paramount:

  • Homes: People with allergies and asthma, as well as those looking to enhance the quality of indoor air, frequently opt for HEPA air purifiers.
  • Hospitals and Medical Facilities: To reduce the danger of infection from airborne microorganisms, HEPA filters are utilized in operating rooms, patient rooms, and other healthcare settings.
  • Industrial Settings: To shield employees from dangerous dust and particles, HEPA filters are used in factories and workshops.
  • Transportation: To improve the quality of the air for passengers, HEPA filters are used in air filtration systems on airplanes and other vehicles.


HEPA Filters Examples

Here are some examples of products that  commonly  utilize  HEPA filters:

  • Air purifiers: Individual air purifiers made for residential or business use.
  • HVAC air filters: HEPA technology is included in certain high-efficiency air filters used in residential air conditioning and heating systems.
  • Vacuum cleaners: Compared to conventional vacuums, HEPA vacuums are made to capture dust and allergens more successfully.
  • Air masks: To shield users from airborne pollutants, N95 respirator masks use filtering technology akin to HEPA.



At your house, place of business, or any other setting, HEPA filters provide a potent way to achieve cleaner air.  You may choose wisely whether to include HEPA filtration in your air purification plan by being aware of its features, advantages and uses.  Because HEPA filters are so powerful, you may breathe easier, live a healthier life, and have the peace of mind that comes with knowing that the air around you is cleansed.


Ella is a skilled embedded systems engineer with experience in PCB design and microcontroller programming. She is committed to following the most recent developments in the field and is constantly seeking for ways to apply them to her work.


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