ULPA vs. HEPA Filters: What’s the Difference? I recently came across an air filter manufacturer who claimed there’s nothing that filters out pollutants quite like a ULPA air filter. And that ULPA filters are even better than the particles and pathogens filtration superstar. But, are ULPA filters actually superior to HEPA filters in terms of removing pollution particulates?
Which is Better ULPA vs. HEPA?
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Both ULPA filters and HEPA filters are exceptional at capturing ultra-small particles. But ULPA filters are thicker and more expensive; however, they’re not as long-lasting. While HEPA air purifiers trap 99.97% of particulate matter with a diameter of 0.3 microns or larger, ULPA filters get even more granular, removing a whopping 99.99% of particles sized 0.12 microns in diameter or bigger. In other words, ULPA filters remove smaller and more particles compared to HEPA filrers. In the final analysis, though, HEPA filters do a better air filtration job, and this post explains why.
Don’t have time to read the rest of this post? No worries, below is a summarized version of the post:
- ULPA stands for Ultra Particulate Air.
- HEPA means High Efficiency Particulate Air.
- Both filter types rely on four different mechanical processes to clean up indoor air contaminants (Find these process below).
- Both consist of a labyrinth of tightly woven fibers.
- ULPA filters are thicker, and that restricts airflow to a degree.
- ULPA filtration systems cost more to install and maintain.
- HEPA filters are cheaper and more durable.
- Both are used in a miscellany of critical industries and cleanrooms.
- ULPA filters are almost exclusively for industrial use while HEPA filters are also used in portable residential air cleaners.
- ULPA filters remove more and tinier particles (99.99% of 0.12-micron particles vs. 99.97% of 0.3-micron particles for HEPA).
To understand the similarities and differences between HEPA and ULPA filters, let’s first define each air cleaning technology.
What Is HEPA Filter?
The acronym HEPA stands for High Efficiency Particulate Air. When manufacturers are making a HEPA filter, they weave a very high number of glass fibers (or a mix of cellulose and polyester fibers in varying percentages) into a dense filtration medium. The result is thick fibrous media that removes solid particles from moving air excellently.
An AC motor draws contaminated air in from the room or space being sanitized. Once the air gets past the prefilter (where applicable), four distinct processes jump into action. Here are the four processes: inertial impaction, sieving, diffusion, and interception.
I’ve explained how these particle removal processes work in an earlier post: True HEPA vs. HEPA-type air filters. From there, the partially clean air flows on to a smell elimination filter that completes the process.
Most HEPA filters today, especially those used in portable air cleaners, also feature a prefilter for capturing larger debris and an activated charcoal filter for odor removal.
What is a ULPA Filter?
ULPA is an abbreviation for Ultra Low Particulate Air. ULPA air filters are similar in structural design to HEPA filters and both work exactly in the same way. Like HEPA filters, ULPA filters are created by compressing numerous layers of fiberglass into an elaborate web of paperlike sheets. Then, the manufacturer folds the sheets into many pleaats, a process that dramatically increases their surface area. But they’re thicker than HEPA filters.
Since ULPA filters are thicker than HEPA filters, shouldn’t they theoretically deliver more comprehensive air filtration? They should. But that’s not necessarily the case when it comes to how real-world air purification systems work.
What Makes ULPA Filters Worse at Air Filtration?
I said above that ULPA filters remove more and smaller particles compared to HEPA. But I also said, at the risk of sounding contradictory, that HEPA filters actually clean the air better. Let me explain.
When it comes to particle filtration, thickness is a good thing. But if a filter is too dense, the excessive density hampers airflow to an appreciable degree. Air filtration experts have found that the extra thickness of ULPA filters cuts airflow by between 20-50%. That’s HUGE.
Suppose you blow the same amount of air through HEPA and ULPA filters for a given unit of time. What’ll happen? The HEPA filter will allow air to pass through it quicker compared to the thicker ULPA filter in the same amount of time.
In other words, ULPA filters have a lower CFM (cubic feet per minute). And an air filter with a higher airflow/CFM outperforms a similarly sized filter with a lower CFM figure.
Why Are ULPA Filters More Expensive Than HEPA Filters?
It’s mainly because ULPA filters are thicker than HEPA filters. To achieve the same performance level as a similarly sized HEPA filter, a ULPA filter should allow more air to pass through in the same amout of time. And for that to happen, it needs to have a stronger motor. It also needs to be larger. Can you now see why ULPA filters cost about 35 percent more than HEPA filters?
HEPA Vs. ULPA Filter Lifespan: Which Lasts Longer?
Both filter types last years, but HEPA outlast ULPA. According to Pharmaceuticalguidelines.com, HEPA filters last about 10 years on average versus 5-8 years for ULPA filters.
Since air flows better through HEPA filters, they don’t need to max out their total filtration capacity all the time. As a result, they’re easier to maintain and last longer compared to ULPA options.
Bottomline: HEPA filters are more efficient than ULPA filters. What’s more, they substantially cheaper. Plus, they have a longer lifespan.
Where are ULPA Filters Used?
ULPA filters are mostly used to sanitize the air in the cleanrooms of various industries including the following:
- Medical industry
- Electronic industry
- Biotechnology industry
- Other applications where there’s exposure to contamination from pathogens and airborne pollution
Even though ULPA filters are exceptionally good at what they’re designed to do, they’re mostly used in industrial air cleaning settings.
Where Are HEPA Filters Used?
HEPA filters have seen massive adoption in a whole range of applications. Players in the medical, electronic, biotech, and automotive industries use them extensively. You’ll also find these air filters in planes and in many complex operations that release toxic particle plumes into the air.
ULPA vs. HEPA: Conclusion
Both are good air filters that different industries use in a wide range of applications. While both see immense use in industrial air filtration, it’s rare to find portable air purifiers with ULPA filters.
And there’s a good reason for that. ULPA air purifiers would be significantly more expensive than similar HEPA options, but they wouldn’t necessarily perform better.
Have you ever owned an air purifier that purifies the air using ULPA filters? Tell me about in in the comments below.
