When considering the best air purifier, consumers may consider a HEPA vs. PECO filter for their device. To understand the difference and which is better, you need to consider how the filters work in even the smartest air purifiers and the standards for both. Additionally, you may want to understand the cost of each. For additional information about affordable air purifiers, check out our guide on the greatest air purifiers under $100.


  • Many consumers and experts believe HEPA filter air purifiers to be the best available air purifiers, either on their own or with other technology.
  • Molekule exclusively sells PECO air purifiers, claiming that the filters alter the airborne pollutants at a chemical level.
  • HEPA filters are significantly more prominent than PECO and PCO filters.

Which is Better: a HEPA or PECO filter?

Both HEPA and PECO filters eliminate airborne particles to improve indoor air quality within a specified space. These two filters work differently on a fundamental level, but both should remove triggers for asthma symptoms and allergens, dust, and mold. Both filters require filter replacement after extended use to continue to be effective. However, HEPA filters must block 99.97% of particulates larger than 0.3 microns in size, while PECO filters have no such standards. Check out our guide to read more about the leading air purifier and humidifiers.

Insider Tip

HEPA filters traditionally hold to one of the highest standards in air purification requirements.

What is PECO?

Molekule introduced photoelectrochemical oxidation (PECO) filters for use inside its air purifiers in 2016. This technology uses UV-A light to create unstable molecules that break apart airborne pollutants, turning each into a harmless organic compound. Molekule claims that its PECO-based cleaners remove particles and allergens in less time than PCO and more efficiently than HEPA ones. However, one company has accused Molekule of false advertising in terms of its comparison to air purifiers with HEPA filters.

With that said, it’s always a good idea to do your own comparisons, which you start by reading our mashups of HEPA vs ionic purifiers, IFD filters vs HEPA filters, and Molekule vs Alen.

How is PECO Different From PCO?

Photocatalytic oxidation (PCO) filters use a catalyst activated by UV light to oxidize airborne particulate matter. This process helps to create non-toxic substances from the pollutants and many studies have shown that this technology can help to increase indoor air quality. The inventor of PECO filters worked off this idea to eliminate toxins, claiming that a PECO filter would be more efficient.

What Makes HEPA Efficient?

A high-efficiency particulate air (HEPA) product has long been considered the best option for an air filter. Because of its fibrous nature, the filter catches particles and traps them along the filter’s surface, eliminating them from the air but not eradicating them. However, combining it with a carbon filter, air ionizer, or electrostatic precipitator may improve results. Proper maintenance will have to be performed over time if you plan to keep the air purifier for many years, so learning how to reset a HEPA air purifier can prepare air purifier owners to keep their devices performing optimally. These cleaners range in price, depending on the highest speed and product quality. However, all HEPA standards must be met for a fiber filter to be certified. Read our Dreval D-950 Air Purifier review for a True HEPA filter unit.

Combining HEPA with Other Air Purifiers

  • Activated carbon filters help eliminate gaseous pollutants like odors, and some even help to eliminate airborne particles. When combined with a HEPA filter, the two may eliminate more particles than a HEPA filter on its own. As a result, these air purifiers may provide a more effective air cleaning method, removing particles and odors simultaneously.
  • An air ionizer uses electricity to charge the airborne contaminants between two plates before pulling them toward the opposing plate. Through this process, the particulate matter becomes trapped on the surface of the plate. Combining a HEPA air filter with an air ionizer could result in particles that slip through the HEPA filter being caught by the ionizer.
  • Electrostatic precipitators with UV light purification irradiate particulate matter before exposing them to UV-C light. Once the light hits the particles, they are neutralized and removed from the air. Combining this technology with a HEPA filter helps to reduce pollutants by having them pass through the HEPA filter first before being exposed to UV light.


Molekule is currently facing a class-action suit regarding the advertising claim that their PECO filters remove more airborne particles than HEPA filters, so be wary of their claims.


What is a HEPA filter?

A HEPA filter is a pleated fiber filter that catches pollutants larger than 0.3 microns in size. These cleaners are currently considered the best on the market.

How does the PECO air purifier work on different pollutants?

The PECO filter changes the pollutants’ molecular composition, turning them into harmless organic compounds.

How often should you change an air purifier filter?

Most air purifier filters should be changed about once a year unless you know your filter becomes dirtier quicker than that. Some air purifiers include an indicator light that alerts you when you need to change your filter.

STAT: Seasonal or perennial allergic symptoms are present in 10% to 40% of the U.S. population, resulting in at least 6 billion dollars in overall health-care expenditures per year. (source)

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