What MERV Rating Are Hepa Filters?

High-Efficiency Particulate Air (HEPA) Filtration is extremely effective at keeping the air in your facility clean. While there are a variety of filters available, you are wondering what Minimum Efficiency Reporting Values (MERV) rating HEPA filters have. You've come to the right place. We've sifted through the internet and researched the answers to share with you.

All HEPA filters have MERV ratings of 17 to 20. True HEPA filters trap 0.3-micron particles with an efficiency of at least 99.97%. 

Continue reading as we talk about the HEPA filter ratings in greater detail. We’ll also tackle its components, operation, limitation and more to help you better understand how a filter's rating affects its efficiency in cleaning the air at your home.

White tower air purifier placed on the corner of the living room, What MERV Rating Are Hepa Filters?

HEPA Filter Ratings

A HEPA filter is the pinnacle of air filters, with a MERV 17 or higher equivalent rating. Dust, pollen, mold, viruses, bacteria, and other airborne particles smaller than 0.3 microns are theoretically removed by this air filter. This is because the 0.3-micron particle size is the most difficult to catch, which is why HEPAs are tested at this particle size. 

Blue replacement filter and an old in need of replacement

To put this into context, let's define a micron. Micron is the abbreviation for micrometer. The size of a micron is one-millionth of a meter. This is much smaller than what the naked eye can see. MERV 17 is the lowest HEPA efficiency, while MERV 20 is the highest.

MERV Filter Ratings

The MERV of an air filter indicates how well it keeps dust and other impurities out of the air stream. Filters with higher MERV ratings catch small particles more effectively than filters with lower MERV values.

Residential, commercial, and hospital HVAC systems’ filters generally filter with a MERV 16 or lower rating. MERV 17–20 filters are often utilized in surgical operating rooms, clean rooms, and other areas that demand extreme cleanliness. 

HEPA Filters' Components

HEPA filters differ from other filters in that they are constructed of thin glass fibers and contain activated carbon. Filter fibers are pleated together into a thick paper-like substance. Particulates in pre-treated air that are unable to pass through the thick, folded surface of the filter will instead stick to it.

Activated carbon develops millions of pores after being treated with oxygen. The surface area of one pound of activated carbon is 60 to 150 acres because there are so many of these tiny pores! It is ideal for absorbing gases and odors due to its large surface area. Chemicals and gases that are too tiny for a HEPA filter to capture bind to the activated carbon's massive surface area.

HEPA Filter Operation

The HEPA filter's fibers are arranged in a pattern that traps particles and prevents them from reentering the atmosphere. Particles are trapped in three ways as air is forced through the filter. 

First, large particles collide with fibers directly and become stuck. Second, because smaller particles travel slower than the air, they get caught in fibers. Lastly, fine particles move randomly through the filter, hitting and sticking to fibers.

Difference between a HEPA-like Filter and a True HEPA Filter

Opening the air filter box of an air purifier

It's worth noting that there are two types of HEPA filters, each with different levels of particle removal efficiency. True HEPA filters and HEPA-like filters are the two types of HEPA filters available.

True HEPA filters are quite costly to produce. Many air purifiers are mislabeled as true HEPA or HEPA-like filters in order to make them more affordable. True HEPA filters have a seal that creates a secure flow of air through the filter material, which allows them to achieve high efficiency.

This filter passed the Department of Energy (DOE) standard which has 99.97% of airborne particles removed.

A filter is technically a HEPA-like filter if it fails to meet the standard percentage of removal rate. Many HEPA-like filters lack a strong seal, that's why not all of the air passes through.

This filter is effective at removing large particles such as pet hair. If you need to get rid of viruses, bacteria, fine dust, or mold spores, a true HEPA filter is the way to go. True HEPA filters are therefore more effective at trapping contaminants than HEPA-like filters.

Advantages of HEPA Filters

In medical settings such as hospitals and clinics, HEPA filters are the standard filtration system. This is due to the fact that high-efficiency air filters remove not only inorganic dust suspended in the air but also microscopic organisms that can cause serious harm. Airborne viruses, bacteria, dust mites, mold spores, and pollen are just a few examples.

Instead of the flat fiberglass media found in most filters, HEPA uses thick, pleated media. According to an HVAC contractor who specializes in AC troubleshooting system services, this will significantly increase the filtration surface area as well as the filter's service life. Improved filtration also helps to keep the interior free of harmful particles all year.

Limitations of HEPA Filters

Though HEPA promotes assurance of maximum air filtration, this  has several limitations too, as shown below: 

  • While a HEPA filter can keep pollutants out of your home, it doesn't ensure 100% complete particle removal. Viruses, bacteria, volatile organic compounds (VOCs), and mold with a diameter of less than 0.4 microns can nevertheless get into your home and contaminate the air you breathe.
  • A HEPA filter can clog and become less effective after filtering numerous types of particles every day. Homeowners are advised to change their HEPA filters at least once, if not twice, a year by many air conditioning repair and maintenance companies, which can be costly.
  • Air must first pass through a HEPA filter to be properly filtered, but even only a single room or a small apartment can be covered by the largest HEPA filter. This implies that only the air in the immediate vicinity can be purified.

What's better than a HEPA filter?

Blue HEPA air filter for an air purifier

Ultra Low Particulate Air (ULPA) filters capture both larger and smaller particles than HEPA filters. HEPA filters remove particulate matter with a 99.97% efficiency with a diameter of 0.3 microns or larger. 

ULPA filters, on the other hand, are 99.99% effective at removing submicron particle matter with a diameter of 0.12-microns or larger. Pre-filters can be used in conjunction with HEPA filters to trap larger particles before they reach the main filter.

The higher efficiency rating of the ULPA filter is due to the higher density of the filter medium, which allows for lower airflow and requires more power to move air than HEPA filters. HEPA filters can last up to ten years, whereas ULPA filters typically last five to eight years. The right filter for your application is determined by your facility's containment regulations and standards.

ULPA filters trap more and smaller particulates, but they are less effective at reducing overall particulate concentration in a typical room than a similar air filtration system with HEPA filters. The dense filter material of ULPA filters reduces airflow, resulting in reduced airflow. ULPA filters pass 20 to 50 percent less air than HEPA filters, resulting in fewer air changes per hour in the room.

Do you really need a HEPA filter?

Replacement air filter for an air purifier

By protecting the HVAC system from dust and airborne particles, the HVAC filter improves its efficiency and longevity. As a result, it is an important but often overlooked component of the system. In addition to protecting the HVAC system from harm, some HVAC filters are designed to increase indoor air quality.

Though HEPA filters offer an array of advantages due to their high filtration efficiency, there are several disadvantages too. Despite their efficacy, HEPA filters are thick and bulky. These qualities can greatly hinder your HVAC system's airflow process. 

If the airflow is impeded, the property's heating and cooling demand will increase, resulting in higher electricity bills and possibly causing damage to the entire HVAC system. As a result, not all residential structures are suitable for a HEPA filtration system. 

Before you install an air filter with a high MERV rating or a HEPA filter, make sure your heating and cooling systems are capable of handling it. An HVAC expert can evaluate airflow and make an informed decision about whether your HVAC system is capable of incorporating in-duct HEPA filtration.

How much is a HEPA filter?

HEPA filters range in price from $16 to $95, depending on quality, size, expected lifespan, and manufacturer. 

Click here to see this HEPA replacement filter pack on Amazon.

HEPA air purifiers range in price from $50 to $1,000, depending on size, quality, and expected coverage area. They are available in most hardware, home goods, and big-box stores, as well as online.

Click here to see this Levoit air purifier, a true HEPA filter on Amazon.

In Conclusion

White tower air purifier placed on the corner of the living room

The filter that traps the tiniest particles is commonly desired by homeowners, such as the HEPA filters with the highest MERV ratings. However, the more effective the filter, the more difficult it is for air to pass through it. As it tries to force air through the filter, this could result in your equipment using more energy. Your HVAC system's life may be shortened as a result.

The investment of a HEPA filtration system, when properly suited for the location, will go a long way towards providing clean air and peace of mind for anyone in the building. 

Thank you for taking the time to read this. Hopefully, we've answered any questions you had about HEPA filters in your search for information. Be sure to check out the related posts below!

How Many Air Filters Does A House Have? [And Where Are Filters Located]

6 Types Of Air Filters For Your Home



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