If you are looking for an air purifier, you would probably come across HEPA filters. In most cases, a salesperson for an air purifier may always say that an air purifier is better if you have one of the HEPA filters. But wait, there are different HEPA specifications you may hear of “true-HEPA”, HEPA-type”, “99%-HEPA”, “HEPA-like”, and so on.  

What are all these?  

So, what is a HEPA filter? How does it work, and how do you choose the best HEPA filter? Here is everything you need to know before buying a HEPA Filter. 

A man wearing full PPE to filter air for breathing
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What is a HEPA Filter?

As officially defined by the US Department of Energy, HEPA stands for High-Efficiency Particulate Air. When associated with a filter, it means a high-efficiency particulate absorbing filter. It is a standard that measures the level of efficiency a filter has in absorbing air particles. To be classified as HEPA, it has to meet specific efficiency levels, such as filtering air particulates as small as 3 microns. It has to have a minimum efficiency of 99.97% and tested according to US Military Standard 282. It has to be individually certified and labeled with specific test results.  

How do HEPA Filters work?

HEPA filters clean the air we breathe through its filter media made of thin fibers of glass and activated carbon material. It captures 99.97 percent of potentially harmful microscopic air particles and traps them on its fibrous surface of tiny twisted glass fibers. There are three different ways a filter captures these small air particles. The first method is interception, when the particles catch the filter’s side and stick to it. The second is called impaction. It is when particles make a direct impact on the filter. The third is called diffusion, where air particles that interact with gases flow through a filter that causes them to slow down and ultimately entangle in the filter. For every 10,000 particles that the HEPA filter trapped, there are about three that can pass through the filter. 

What are the MERV Rating in HEPA Filter?

MERV Rating plays a vital role when it comes to air filters. MERV is an acronym for Minimum Efficiency Reporting Value. It is a standard that measures the filter efficiency in removing air particulates from 0.3 microns to a larger size. MERV uses a scale of 1 to 20, with one as least efficient and 20 as the best and most efficient. The MERV must serve as a guide in choosing the air filter that suits best the household need.  

Most household is recommended to follow a MERV rating of 8 to 13 because filters in this rating are best at removing 90% of fine particles such as smoke, bacteria, pollens, mold spores, and other larger air particulates. It is efficient in improving indoor air quality and removing allergens for people with respiratory issues.  

MERV Rating with 1 to 4 and 5 to 7 have no notable difference. Filters in this range have the lowest price but can strain large particles such as pet hair, carpet fibers, and heavy dust. The good thing about using a filter in these ratings is that it can prolong the HVAC system’s life as it will not cause much strain to the unit when air passes through the filter.  

On the other hand, MERV ratings of 14 to 16 and higher are mostly used in specialized environments such as hospitals, commercial, and industrial. These filters are expensive to acquire and maintain. These are not suitable for home use as these filters are not compatible with the household HVAC system.  

HVAC System
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What are the different types of HEPA filters?

As marketing can instantly boost HEPA filters’ sales, businesses have their way of classifying HEPA air filters from other competitors. Here are the main types of HEPA filters that you may encounter.

ULPA Filters

The Ultra-Low Particulate Air has the highest MERV rating, which is 18. The tight fibers in the filters and larger surface area will remove pretty much of the smallest particles. But, these filters can be pretty much expensive. Because of its cause, there are very few HVAC that uses this kind of filter.

True HEPA Filters

True HEPA filters have a MERV rating of 17. It is perfect in reducing the number of allergens at home and can efficiently remove small particles like mold spores, pet dander, dust mites, fine dust, and pollen. These are recommended for people with respiratory ailments. Though it cannot cure illnesses, it can significantly improve indoor air quality and remove triggering factors.

HEPA Type filters

HEPA Filters are the same as True HEPA Filters. Manufacturers use to put True to ensure the buyers that they genuinely meet the basic MERV standards.


Filters in this classification do not pass the MERV standards. These are regular air purifiers, only that they use this classification as a form of enticement in marketing these products.  

Different types of HEPA filters?
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Benefits of Using HEPA Filter

Using HEPA Filter at home is more beneficial than using a regular filter. It can capture pet dander, pollen, smoke, and dust known to trigger allergies and other respiratory illnesses. It can improve indoor air quality by efficiently trapping even the smallest air particles. It can also help in masking unpleasant odors such as mold. It can improve efficiency and prolong the HVAC system’s life as less dirt and dust can enter the system.  

HEPA Filters are widely used in many industrial applications such as pharmaceuticals, aerospace, and technology industries. Even the nuclear industry uses HEPA filters to help prevent the spread of radioactive particles.  

Disadvantages of using HEPA Filter

Using a HEPA filter can also have disadvantages. One of these is its inability to trap other harmful pollutants such as gases, fumes, and chemicals. Many volatile organic compounds are carcinogens and can pose unfavorable health effects. These cannot be trapped because it is a lot smaller than 3 microns.   

Another is the cost of replacing filters. Depending on how many times you change the filter, filter replacement is costly. Moreover, the unit’s shape and compactness rely on the air purifier installed in the HVAC system.  

HEPA filters can also be a breeding ground for molds and bacteria. Due to its size, molds and bacteria are trapped in the filter. If a homeowner fails to replace the dirty filter, molds and bacteria will thrive in this environment. It will multiply in numbers and get released back into the air. Thus, it will possibly be the source of many air-borne infectious diseases.   

Without proper monitoring system you could be changing your filters as frequent as you could without considering its cost efficiency or you are probably not changing it as constantly as needed that you are inhaling dangerous air particles already.

Should I buy HEPA Filter?

HEPA Filters must be weighed in with their benefits and shortcomings. It is not the complete solution to addressing indoor pollutants. While it can be a solution to improve the indoor air environment, other particulates cannot trap, such as volatile organic compounds. If you, as a homeowner, are more concerned about larger particles such as dust, pollen, dander, and anything that is larger than 3 microns, then the HEPA filter is right for the HVAC system at home.  

Can you wash a HEPA filter?

There are washable HEPA filters. Rinsing it under cold water should clean it. If it is filthy, then soaking it in hot water is also an excellent way to clean the filter. If it is not washable, using a vacuum cleaner can suck away dust and debris from its surface.

How long does the HEPA filter last?

HEPA Filters may last up from two to three years, depending on the setting inside the household. There are some ways to make the filters last up to three years. One way is to maintain the cleanliness inside the house. With the use AKCP Air Quality Sensors, you will know when is the right time to clean or replace these filters. The sensor is able to measure the mass concentration of particles in the PM1.0 to PM10 range and particle number concentration in the PM0.5 to PM10 range. This air particle sensor is also utilized for indoor air quality (IAQ) assessments of clean rooms and workplaces. 

Opening the window to allow fresh air to enter is also right so that the filter will not be easily soiled. It is also important to vacuum frequently and replace the carpets with other materials such as wood, tile, or vinyl. Keeping the pets outdoor can also reduce pet dander that can heavily contribute to the filters.  

Are HEPA filters worth it?

As indoor air is more pollutant than outdoor, it is crucial to invest in an air purifier for the HVAC system with proven technology. The air purifier can only work best and efficiently when there is a HEPA filter installed. Investing in a good HEPA filter can assure the homeowners of a favorable indoor air environment that is especially great for new parents with newborn and younger children. HEPA filters are also worth investing in for homeowners with asthma and other respiratory issues as they can keep the triggering allergens at bay.

Kid blowing her nose due to allergies.
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Which HEPA filter is best?

It is essential to learn the different features of most HEPA filters available in the market. Before buying any HEPA filter, it is necessary to identify the needs. If you have newborn and younger children and people with asthma, then the HEPA filter that could best address the situation is classified as TRUE HEPA filters or HEPA Type filters. As long as it is properly monitored it is always worth the money. Your safety must always be a priority.

Visit www.akcp.com for more professional monitoring solution for your HVAC System. Their extensive experience in the industry proves the professional and guaranteed customer service in HVAC solutions. 









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