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Medical Grade HEPA vs True HEPA vs HEPA Type

First marketed in the 1950s, the HEPA filter is a filtration system that is now a common feature in home air quality equipment. They ensure better air quality and thus improve the quality of life, especially for those suffering from allergies and asthma.

But you have to know that there are various types of HEPA filters. And the type you choose determines the filtration efficiency – which usually ranges from 99% to 99.995%. In this Medical Grade HEPA vs True HEPA vs HEPA Type comparison article, we’ll see what HEPA filters do and compare between the three types mentioned.

What does a HEPA filter do?

HEPA, the short form for High-Efficiency Particulate Air (filter), removes up to 99.97% microscopic particles of around 0.1 to 0.3 microns from the air, according to the EPA. HEPA filters capture particles through sieving, inertia impact, interception, and diffusion. They, therefore, reduce airborne pollutants and improve indoor air quality.

History of the HEPA filter

Contrary to what one might think, the technology behind HEPA filters is by no means a fad of recent years. Developed in the 1940s, it was commercialized in the ’50s during World World War II. In the 1960s, they were deployed for use in hospitals for the prevention of airborne germs.

Today, they are mainly integrated into air purifiers, robot vacuums, and electric brooms. These are found indoors in apartments, offices, and commercial spaces.

HEPA filters are now also used for cleaning particulates in the nuclear sector. In addition, they are in other fields including medical, pharmaceutical, and chemical industries.

How HEPA filters capture particles

Each HEPA filter is made up of thousands of glass fibers (fiberglass). They are intertwined to form a sort of labyrinth capable of arresting microscopic particles.

HEPA filters work by trapping contaminants as they pass through the network of fibers. As pollutants pass through the filter, they are trapped in one of the four stages: diffusion, interception, inertial impact, and sieving.

Benefits of air purifier with HEPA filter in the home

Individuals with allergies or asthma can feel a substantial relief when using a HEPA filtered air purifier.

The fine mesh fibers effectively capture particulates such as dust mites and mold spores which are common allergy triggers. For those who have pets in the home, a HEPA filter also helps trap pet hair.

HEPA filter-equipped air purifiers also help your HVAC system trap dirt and dust, ensuring they don’t accumulate within the system.

HEPA filters have also become increasingly important since the Covid-19 pandemic. They have been proven by science to help reduce viruses indoors and thus reduce the spread of coronavirus. According to the CDC, using masks and HEPA air cleaners can reduce COVID-19 exposure by 90 percent.

Medical Grade HEPA vs True HEPA vs HEPA

The real efficiency of a HEPA filter machine is determined by the type of filtration system. There are three known HEPA filters: the Classic HEPA filters, medical-grade HEPA filters, and the true HEPA filters. What’s the difference between each?

The classic HEPA filter

Classic HEPA filters remove 99% of dust particles measuring as little as 2 microns from the air. These particles include allergens, chemicals, dust, and many more. However, HEPA filters are the least efficient type of filters available on the market. They don’t meet the same industrial standards True and medical-grade HEPA filters have.

Tips: Particles and microorganisms are always measured in micrometers (1 micrometer = 1 millionth of a meter). With our eyes, however, we can only see particles larger than 10 microns.

True HEPA filter

True HEPA filters are filtration systems that capture up to 99.97% of particles measuring as small as 0.3 microns from the air, according to the NCBI. 0.3 microns are the most penetrating particle (MPP) size that bypass filter systems. This size of particle will easily penetrate a classic HEPA filter but will be captured by a True HEPA filter. These particles can be bacteria, viruses, pollen, mold, dander, or other microorganisms.

For a HEPA filter to be called a True HEPA filter, it must be equipped with a certification. Reliable certifications are issued by the EPA, AHAM, ASHRAE, among others. This certification must prove that the filter has been tested to effectively remove 99.97% of particles as small as 0.3 microns from the air.

Air purifiers with True HEPA filters are recommended for smokers, and those who have pets. They’re ideal for removing smoke, odor, pollen, pet dander, and dust.

Medical-grade HEPA filter

Medical-grade HEPA filters are the most effective for air filtration. While True HEPA filters are classified in the range of H10 to H12, HEPA filters considered medical-grade are categorized as H13 filters. They can filter down to 0.1 microns.

If True HEPA filters can capture 99.97% of particles, medical-grade HEPA filters can remove up to 99.995% of particles. That’s almost no chance for microbes!

Air purifiers with medical-grade HEPA filters are recommended for people with seasonal allergies. They’re also ideal for catching viruses. Unfortunately, not all air purifiers with so-called medical-grade HEPA filters are actually medical-grade.

Most only qualify as True HEPA filters. But one way to confirm if they truly are is by checking the HEPA certification and filtration efficiency. It must be either H13-rated, with the ability to capture 99.995% micro particles that are as small as 0.1 microns.


How long does a HEPA filter last?

In a polluted or commercial environment, a HEPA filter loses a quarter of its efficiency over 6 months. So, a HEPA filter can last for 6 months to 3 years, depending on the environment. Then, it can be changed, cleaned or washed. More details on durability are usually provided by the manufacturer. So check out the instruction manual, if there’s one.

Do you need to clean a HEPA filter?

It is always recommended that the HEPA filter be replaced with a new one. But, if you really want to do the dirty work, you may decide to wash or clean the filter and reuse it.

However, you will first have to understand which type of filter you have. Is it a washable HEPA filter? If it is, you will first have to remove it from the appliance. Then, wash it under cold water without coming into direct contact with the central part of the filter (the fibers) because it is very fragile. Finally, wait for it to dry before reassembling in the machine.

If it’s a permanent HEPA filter, do not wash it! Only use a vacuum cleaner to remove debris and excess dirt.

What size air purifier do I need?

In general, you need about 100 CFM for every 250ft² of room space. To get the square footage of your room, you will need a tape measure and a friend. Measure the length and width of your room in feet. Multiply the two numbers, and this will give you the size.


HEPA filters are among the most commonly used and effective filters in air quality appliances. While there are many types of HEPA filters, medical-grade HEPA filters are the most effective. They can remove up to 99.995% of particles that are 0.1-micron diameter in size or larger.

True HEPA filters are also highly effective and can catch up to 99.97% of particles that are not lesser than 0.3 microns. The regular HEPA filter air purifiers are the least recommendable as particles of 1.99 microns and smaller are let free.

As you’ve learnt, air purifiers with medical-grade and True HEPA filters are ideal for catching microbes and particles such as viruses, bacteria, fungi, mold, dust, smoke, pet dander, and more.

Odutolu Timothy

Passionate about technology and communication, Timothy Odutolu has more than 5 years of experience writing for various niches in these fields. He's more comfortable writing about the key trends in the business-to-business software-as-a-service (B2B SaaS) niche. He is also a generalist with interests in journalism, DIY and outdoor, and other writing services. He's reachable via Twitter, LinkedIn, and email through or

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