HEPA Vs. True HEPA – What’s the Difference?


If you’re shopping around, odds are that you’ve come across a whole lot of air purifiers and air filters that throw around the word “HEPA”. Some say True HEPA, some say “HEPA Type”, some say Medical Grade HEPA, some say HEPA and then have a number after it.

Yeah, it’s a lot to take in.

At the end of the day, however, it’s a lot more straightforward than you might think.

A HEPA Type filter is inferior to True HEPA filters in every way. They cannot capture particles as well as True HEPA filters, nor can they capture smaller particles as efficiently as True HEPA filters. True HEPA filters include Medical Grade HEPA filters and HEPA-10, 11, 12, & 13.

HEPA Vs. True HEPA - What's the Difference? 5

“HEPA Type” filters simply do not measure up to real HEPA filters.

Below, I made a chart comparing “HEPA Type” filters against True HEPA filters. Please note that I use “HEPA Type” as a broad term for filters that bad businesses try to trick people with. Other fake HEPA filter phrases that I’ve seen are “HEPA-like”, “99% HEPA”, and “HEPA-style”. Long story short, if you see anything like that on an air purifier or an air filter, then it’s not a real HEPA filter. It’s a knockoff. Run away!

Another thing that I have to note, now that I’ve told you what the fakes call themselves, is that real HEPA filters also come with different names. Those names include “Medical Grade HEPA”, “HEPA-10”, “HEPA-11”, “HEPA-12”, “HEPA-13”, “3 in 1 True HEPA Filter” and a whole lot more. Also, “3 in 1” and other such filters just means that the filter you’re buying has a few different filter types built into one combo filter. I’ll explain that later.

With all of that out of the way, here’s the chart!

“HEPA TYPE” FILTERTRUE HEPA FILTER
HEPA Vs. True HEPA - What's the Difference? 6HEPA Vs. True HEPA - What's the Difference? 7
Usually 90-95% effective against particles 2 microns and larger.99.97-99.99997% effective against particles .3 microns and larger.
Better filtration overall.
Better filtration against smaller particles.
MERV RATING: Usually 13-16MERV RATING: 17-20
Higher (better) MERV rating.*
Technical Breakdown of MERV Rating:**
.3-1 micron – ~75-95%
1-3 microns – 90-95%
3-10 microns – 90%
Technical Breakdown of MERV Rating:**
.3-1 micron – 99.97-99.99997%
1-3 microns – 99%+
3-10 microns – 99%+
As you can see, True HEPA filters are much, much better at capturing particles of all sizes. They are especially good at capturing particles smaller than a micron.
Lower Density FilterHigher Density of Filter
A denser filter leaves less room for particles to come through, making a True HEPA filter better.
Effective Against:
Dust Mites, Pollen, Large and Small Dust, Mold Spores, Dander, Cooking Dust, Flour Dust, Bacteria, Smoke, Sneeze Droplets, Respiratory Droplets
Effective Against:
Dust Mites, Pollen, Large and Small Dust, Mold Spores, Dander, Cooking Dust, Flour Dust, Bacteria, Smoke, Sneeze Droplets, Respiratory Droplets, Some Viruses, and other particles as small as .3 microns.
I will note that the “HEPA Type” filters can capture a lot of stuff (almost as many as a True HEPA filter), however, they aren’t as efficient.
Replacement Filter Cost: $5-30
Can be cheaper, but I think we can see why!
Replacement Cost: $5-75
Comparable price most of the time–largely thanks to years and years of industry improvement!
Also Known As:
“HEPA Type”
“HEPA-like”
“99% HEPA”
“HEPA-style”
Also Known As:
True HEPA
Medical Grade HEPA
HEPA-10
HEPA-11
HEPA-12
HEPA-13
Table Breaking Down True HEPA Filters Against HEPA Type Air Filters. Note, a Quality Air Filter is Required to Make an Air Purifier Work Well!
Sources: AirFuji, US EPA, ISO Aire, National Air Filtration Association, Lakeair, and Amazon.com

*Believe it or not, MERV 17, 18, 19, and 20 filters are usually used in clean rooms, surgery rooms, and other places where even a spec of dust can be a huge problem! (Sources: Grainger and Second Nature) There is talk that people don’t need filters that are MERV 17 and higher in their homes (they say it’s overkill), but, since the prices are often comparable, there isn’t really a reason against it–especially during flu season!
**The Technical Breakdown of MERV ratings takes the result of the lower boundary (i.e. MERV 13) and then the result of the upper boundary (i.e. MERV 16) to provide a range.

HEPA Type Versus True HEPA Filter Comparison Explained

Now, I know that not everyone likes visuals and that they aren’t the best way for everyone to learn, so I’m going to explain everything a little deeper here. I’ll address things row by row for you all. (And I’ll get into things a little deeper here too.)

Air Filter Effectiveness

As I already outlined “HEPA Type” filters aren’t nearly as effective as True HEPA filters. At best, they can only cleanse the air of around 95% of particles larger than 2 microns. For particles as small as .3, “HEPA Type” filters can be 75% or less effective.

Conversely, True HEPA filters (the real ones), are 99.97% effective at a minimum across the board.

And, since I just addressed some things here that come later on in the Technical Breakdown of MERV, I won’t be including that bit. It would just be redundant.

MERV Rating

Before I start, let me just say that “HEPA Type”, and other such names for the knockoff HEPA filters, might not have actual MERV ratings. Some won’t even be in the 13-16 range. Because of this, I can almost guarantee that there’s no knowing what your MERV rating for your filter will be–except for if it’s written out on the filter.

Conversely, things are very straightforward with real HEPA filters. You know for a fact that when you get a HEPA filter the MERV rating will be at least 17. Because of that, it can be a whole lot simpler to just purchase a real HEPA filter instead of the sketchier knockoffs and fakers.

Density of the Filter

The denser the filter the better it will be at filtering out smaller particles. True HEPA filters are very dense and they’re also very efficient with the power they require too.

Air filters that are just “HEPA Type” and other such phrases usually have less dense filters, which is a big reason why they aren’t able to capture smaller particles. Because of this, real, True HEPA filters take the win again.

What Are HEPA Type and True HEPA Filters Effective Against?

As was the case with the MERV rating for “HEPA Type” filters, there is no guaranteeing anything when you are getting a wannabe HEPA filter. You’re buying an inferior product that the manufacturers skimped on. Since they skimped on making the filter, you can basically guarantee that they skimped on testing them too. Because of this, you can’t be sure what you are actually going to see get stopped by your “HEPA Type” filter.

However, if your HEPA-Type filter lands in the range of MERV 13-16, then it will be able to capture almost everything that a True HEPA filter (the real ones) can. The only differences will be that the MERV 13-16 ones aren’t doing it as effectively as real HEPA filters and the MERV 13-16 “HEPA Type” filters won’t be able to capture viruses, or effectively catch particles smaller than .3 microns.

Long story short, “HEPA Type” filters aren’t nearly as effective, but they can sort of catch most of the things that real, True HEPA filters can catch. (Again, they just can’t do it as well, and that’s even if they are MERV 13-16, which isn’t guaranteed.)

Cost Comparison Between HEPA Type Filters and True HEPA Filters

And finally, we have the cost.

I know, you might have been dreading this.

However, let me just say that a whole lot of air filters–be it a real HEPA filter or a fake–are priced similarly.

This wasn’t always the case, and there are still outliers, but, by and large, I find that there are a lot of real HEPA filters of varying levels that have prices that are close to (and sometimes better than) the fakers with the “HEPA Type” filters.

Again, this isn’t always the case and you should shop around, but real HEPA filters don’t break the bank anymore, at least not all of them. If you don’t want to shop around for an air purifier with inexpensive replacement filters that are real HEPA filters, then I invite you to check out my list of recommendations, all of which have True HEAP filters. You can check them out here: Air Purifier Essentials Top Picks: Best HEPA Air Purifiers on the Market. (And yes, I own the majority of the ones on the list–those I don’t, I own at least one air purifier made by the company.)

With all of that said, I will add that there are a whole lot of good air purifiers (not just the filter, but the actual air purifier unit) that have real HEPA filters that are very affordable. Some of the fake HEPA filters are cheaper, sometimes, but that isn’t always the case anymore. (Again, check out my list of recommendations because those are some of the best ones for their prices!)

Other Things of Note – MERV Ratings and Air Filters

All real HEPA filters (and not just “HEPA Type” filters) will have a MERV rating of at least 17, according to ISO-Aire. A MERV rating, for those who aren’t air quality experts, is simply just a rating that tells you how effective your air filter is at capturing particles between .3 microns and 10 microns, according to the EPA.

“MERV” stands for Minimum Efficiency Reporting Values and it’s just a measure for rating filter efficiency.

What Are 3 in 1 and Other Such HEPA Filters?

A lot of air purifier manufacturers sell filters that are 3 in 1, 5 in 1, and other similar things. (3 and 5 seem to be the most common.)

The question is, “What is a 3 in 1 filter?”

In short, 3 in 1 filters are air filters that have three different types of filters all bundled into one single unit. A common combination for 3 in 1 air filters is a pre-filter, a True HEPA Filter, and then an activated carbon/charcoal filter.

And before anyone yells at me, this is the same sort of thing for 5 in 1 and other such air filters as well. 3 in 1 is just the most common.

There are a lot of perks to getting an air filter that has several things built into it, for starters, they’re usually a bit cheaper than if you have to buy three separate filters. In addition to that, they’re really easy to maintain too–you can replace just one filter instead of several.

HEPA Vs. True HEPA - What's the Difference? 8

As you can see in this little picture that I took of the filters in my Levoit air purifier, there are two very different things going on!

One is black, the other grey.

So, the black part is actually on the back of the grey one too–both filters are identical.

The black part, as you might already know, is the activated carbon part. That’s there to filter odors and gasses.

The grey part is actually two different filters. The first bit is a tight screen that will capture most of the bigger dust. That’s called a pre-filter. Beneath the tight screen is the actual HEPA filter, and that’s what captures all the .3 micron things like bacteria, some viruses, and a whole lot more.

By having all three of those filters built into one, it ensures that I can get the cleanest air that I can get with ease!

And, as I mentioned before, it is a whole lot easier to maintain and keep up with than having multiple filters to worry about–an issue I have with another one of my air purifiers.

And with all that said, I hope this article helped you all! If you’d like to keep reading, here is a list of articles that I’ve written that might interest you!

Are Air Purifiers a Waste of Money? | The Worth of a Good Air Purifier

Are Air Purifiers a Waste of Money – How and Why Air Purifiers are Worth the Cost

What Are Air Purifiers For?

What is a Water Based Air Purifier? | The Pros & Cons of Water Air Revitalizers

What is a Pre-Filter? Does My Air Purifier Need a Pre-Filter?

Jonathon Silva

Jonathan Silva is our longtime Air Purifier Essentials author. He has been writing on air purification technologies for his entire professional career.

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