PECO vs. HEPA | How Do They Compare?

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Written By Jamila W.

PECO filter technology is an innovative solution for the effective removal of pollutants from indoor air. But how does it compare with HEPA, the industry standard for efficient air filtration? In this article, we compare the PECO filter vs HEPA to help you evaluate which type of filter is the best choice for an air purifier. 

PECO Filter vs HEPA: Side-by-Side Comparison

PECO FilterHEPA Filter
Full namePhotoelectrochemical oxidation (PECO) filterHigh-Efficiency Particulate Air filter
What is it:A catalytic air filter that uses photo electrochemical oxidation to destroy indoor air pollutantsA particulate arrestance filter
Initial release:2014During the 1940s (updated in 1983)
Developers:Dr. Dharendra Yogi Goswami,Clean Energy Research Center, University of South FloridaMolekuleArthur D. Little,The US Army Chemical Corps and National Defense Research Committee,The Manhattan Project,The US Department Of Energy
Filter types/structure:Fibrous corrugated filter coated with a proprietary nanocatalyst A pleated fibrous mat with randomly arranged fiberglass or polypropylene fibers
Minimum particle size filtered:0.3 micrometers0.3 micrometers
Percentage of particles removed:99.97% minimum (via HEPA pre-filter). Unknown efficiency of the catalytic filter.99.97% (ASME, U.S. DOE)
Types of particles removed:Volatile organic chemicals (VOCs)OzoneVirusesBacteriaMoldCigarette smokeParticulate Matter (PM 1, PM2.5, PM10)Particulate matter (PM2.5)Bacteria Viruses Cooking oilSmoke  Insecticide  dustPollen  Fungal sporesRespiratory dropletsLead dustDust mites
Cleaning/replacementPECO HEPA pre-filters are replaceable. PECO catalytic filters should be changed every six months.Washable HEPA filters can be rinsed under running water.
Applications: Commercial and industrial HVACAir purification in hospitality settingsGeneral hospital air cleaning  Allergy reduction in domestic environmentsHospital air filtration (including operating theaters) Air filtration in the nuclear industryAir filters for the electronics sectorAir filtration in the food and beverage sectorAir filtration in HVAC and appliances

What is a PECO filter? 

A photoelectrochemical oxidation filter or PECO filter is a proprietary air filter developed 20 years ago by Dr. Dharendra Yogi Goswami, an eminent engineer from the University of South Florida. His company, Molekule manufactures professional and consumer air purifiers that use the PECO filter to remove and destroy pollutants in indoor air.

The PECO filter is a photocatalytic filter that harnesses UV light and electricity to degrade and destroy particulates and gaseous organic contaminants in room air, including volatile organic chemicals (VOCs). 

PECO air cleaners also carry a pre-filter (HEPA filter) to remove larger particulate contaminants from the device’s room air intake before it is treated by the PECO filter.  PECO air cleaning technology received FDA clearance as a Class II medical device in 2018.

How do PECO filters work?

PECO catalytic air filters destroy indoor air pollutants by generating hydroxyl oxidative species (free radicals) from water vapor in indoor air. The fibers of the filter are coated with a proprietary nanocatalyst that is activated by  UV-C light (blue light – 222 nm) and potentiated by an electrical current to generate high concentrations of reactive oxygen species. The fibrous filter maximizes the surface area of the filter for efficient air cleaning.

Air pollutants that come into contact with the filter are adsorbed onto the activated catalytic material. The powerful oxidants present disrupt the molecular bonds of organic pollutants, destroying them. The oxidation reaction only leaves water, carbon dioxide, and harmless mineral detritus that can be released in exhaust air.

What do Molekule PECO air filters remove?


In laboratory settings, the photoelectrochemical action of PECO air filters has been demonstrated to destroy a wide range of air pollutants and odors. The oxidative action of the PECO filters is effective on organic (carbon-containing) air pollutants including:

  • Volatile organic chemicals (VOCs)
  • Formaldehyde
  • Cigarette smoke
  • PM1, PM2.5, and PM10 particulates
  • Biological aerosols including viruses, bacteria, mold, and pollen
  • Ozone
  • Pet dander and dust
  • Nitrogen dioxide 

PECO air filters cannot remove all pollutants from indoor air. A PECO air filter will not remove or reduce:

  • Carbon monoxide
  • Radon gas 

PECO filter formats and maintenance

Molekule’s PECO filters are designed for exclusive use in PECO air purifiers. They come in three formats suitable for the following PECO air cleaner models:

  • Air Mini+ is a small portable air cleaner 
  • Air Pro (a performance air cleaner)
  • Pūrgo™ (an industrial/professional air cleaning solution)

According to Molekule, PECO filters cannot be cleaned.[1] However, they are designed to be replaced frequently as the catalytic coating has a finite life span. Molekule recommends that PECO filters are replaced every six months for optimal air cleaning. [2] The pre-filter should also be checked regularly and replaced if saturated with dust, dander, and particulates. 

What is HEPA?

purifier filter

HEPA stands for:

  • High-Efficiency Particulate Air
  • High-Efficiency Particulate Arrestance 
  • High-Efficiency Particulate Absorbing 

It is a type of fibrous air filter that has been standardized for over 70 years. HEPA filters contain a fibrous filter media with a high surface area for capturing particulate air pollutants. The fiberglass, acrylic, or polyester fiber mat attracts and retains airborne particulates in indoor or outdoor that are passed through the filter.

HEPA air filters are known for their efficiency that meets standards set by the U.S. Department of Energy and the American Society of Mechanical Engineers (ASME). 

The development of HEPA

HEPA air filters were developed by The US Army Chemical Corps and National Defense Research Committee as part of The Manhattan Project in World War II. HEPA filters were relied on to remove radioactive particles from air breathed by personnel who worked in the development of the atomic bomb. 

After the war, this efficient filter design was commercialized and eventually became an internationally recognized standard for air filtration. In the 1980s, HEPA performance standards were updated by the American Society of Mechanical Engineers (ASME) to reflect the wide range of applications where the filters are used.

HEPA filter performance 

HEPA filters are internationally recognized as being high-efficiency. Unlike many emerging air filtration technologies, HEPA filters have been fully tested and internationally certified (ISO 29463) with a strong evidence base for their performance. 

HEPA filters are rated according to the size of particles they filter from indoor air. They are effective at removing particles with diameters as small as 0.3 microns, with 99.97% efficiency. This makes HEPA filters extremely effective at removing:

  • Dust
  • Dirt 
  • Pollen
  • Aerosols
  • Biological agents including bacteria, viruses, and mold

In mechanical air purifiers, HEPA filters will strip room air of particulate matter down to PM2.5 size. However, it cannot remove gaseous air pollutants like carbon monoxide, radon, or VOCs.

Limitations of HEPA filter technology

HEPA filters are industry-standard filters for air cleaners. However, they do have several limitations:

  • Unless a HEPA filter has been designed to be washable, it will require replacement once it becomes full and the air-cleaning performance of the filter deteriorates.
  • Used HEPA filters are a pollutant sink and need to be carefully handled and disposed of.
  • HEPA filters can increase the energy consumption of HVAC systems and air cleaners that pull indoor air through the filter. 

PECO Filter vs HEPA: What’s the difference?

PECO and HEPA filters are both used in performance air purifiers. Both air cleaning technologies can substantially improve air quality. But there are marked differences between the two types of filters, which affect the applications they are suitable for. Here are the need-to-know differences between these two air filters:

1. Mechanism of action

PECO and HEPA filters work in different ways to clean indoor air. HEPA filters have a primarily mechanical action, using their randomly arranged fibers in high surface area pleating to trap particles that pass through the filter. 

PECO filters contain a UV-activated catalyst, generating free radicals that destroy air pollutants that come into contact with it. Rather than simply trapping pollutants, a PECO filter turns them into harmless water, carbon dioxide, and detritus.

2. Pollutants filtered

The most important difference between these two air filters is the range of pollutants they reduce and remove from indoor air. HEPA filters operate in mechanical air cleaners to physically arrest particulates that pass through them. They cannot remove gaseous pollutants from indoor air.

PECO filters have the advantage of reducing or removing both particulate and gaseous pollutants. Unlike HEPA filters, they can eliminate VOCs, ozone, and nitrogen dioxide. 

3. Efficiency

HEPA filter efficiency is internationally standardized. For an air filter to be a HEPA filter it must remove a minimum of 99.97% of particles that are 0.3 microns in diameter or larger. Because HEPA filters have proven performance, they are a reliable choice for air cleaning.

The Environmental Protection Agency has noted the lack of rating metrics and efficiency standards for emerging air cleaning technologies like PECO. This means that consumers are reliant on the information provided by Molekule to evaluate efficiency. PECO air cleaners do contain a HEPA pre-filter that removes particulates from the air before it passes to the PECO filter. 

4. Applications

The applications of PECO and HEPA filters are comparable. Both filter types are used in high-cleanliness settings like hospitals. But as a more established air cleaning technology, HEPA filter use is much more widespread.

5. Formats

HEPA filters come in a wide range of sizes and formats. This makes it easier and cheaper to replace a generic HEPA filter in an air cleaner. PECO air filters are specifically made for PECO air cleaners and cannot be used with other air purifiers. PECO air cleaners also only accept authentic PECO air filters.

2. Cost

HEPA technology has been around for decades. It is no longer under patent and so can be used in air cleaning and filtration devices at a variety of price points. PECO is a proprietary technology that is currently expensive. PECO air cleaners were currently retail for prices upwards of $500 and individual replacement PECO filters cost over $100.

Closing thoughts

yoga at home

PECO and HEPA filters are both excellent choices for effective air cleaning. Though HEPA is the more established and standardized of the two, PECO filters have a more sophisticated mechanism of action that can eliminate a wider range of indoor air pollutants