What is the Difference Between a HEPA Filter and an Air Purifier?


Let’s face it, completely new technologies can be really confusing. I get it. So, here’s an answer to a really simple question that I’ve seen asked several times.

The difference between a HEPA filter and an air purifier is that a HEPA filter is a part of an air purifier, it’s just the filter. An air purifier is the broader machine and it is made up of the filter, fan, body, and whatever other system it might have.

HEPA filters are just a piece of the whole, it’s something that you are supposed to easily replace whenever its needed. An air purifier, being the whole machine, isn’t what needs replaced.

The reason why so many air purifiers are called “HEPA air purifiers” and other similar phrases is because the HEPA filter is one of the most important parts in the air purifier. Without a filter, the air purifier wouldn’t work.

Not every air purifier has a HEPA filter, so the distinction that an air purifier has a HEPA filter is what makes it special. It’s what someone will look for when they’re shopping for an air purifier. The air purifier’s identity is tied up around the filtration system that it uses.

There are other air purifiers out there that also take their names from their filters and systems. One such air purifier is a water-based air purifier, which, as I’m sure you can tell, uses water as its filter. Those are one of my favorite air purifiers, so I wrote a few articles on them. You can check out a few of them below.

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

What Is the Best Air Purifier That I Can Buy? | Water Based Air Purifier Buying Guide

How Well do Water-Based Air Purifiers Work?

So, What is a HEPA Filter?

A HEPA filter is a specialized kind of filter that was originally created as part of the Manhattan Project (where the United States developed the atomic bomb). It was designed to capture dangerous radioactive materials from the air.

In time, people learned that these same filters could be of great use in homes as well. These filters can capture 99.97% of particles that are larger than .3 microns. That’s pretty small! How small? Well, that’s about 57 to 603 times smaller than a human hair. (The range exists because some people have thicker hair than others.)

So, why is that important?

Particles smaller than .3 microns are pretty incredibly small, as I’m sure you’ve ascertained by now. The fact that HEPA filters can filter particles that small bodes well for us because dust, pollen, dander, and tons of other particles that float around in the air are all larger than .3 microns. As such, a HEPA filter can pull them all out of the air.

But there’s a lot more to HEPA filters too, a lot of air purifiers that have HEPA filters have other filters built into them. These other filters include activated carbon filters and pre-filters, both of which can help you get better, cleaner air. There’s a lot to know about air purifiers, but that’s for another day. If you’d like to learn more bout activated carbon filters, check out this article, How Do Activated Carbon Filters Work in Air Purifiers? | 3 Things Activated Carbon Filters Clean from the Air to Make it Better for You. If you’d like to read some more on pre-filters, check out this one, What is a Pre-Filter? Does My Air Purifier Need a Pre-Filter?

Why Do So Many Air Purifiers Have HEPA Filters?

HEPA filters have become just about standard across all the air purifiers for several reasons. For starters, they’re pretty easy to manufacture nowadays thanks to so many years of development. On top of that, these air purifiers are incredibly effective, especially for their cost.

I’d argue that HEPA filters have gotten to the point that the phrase “HEPA” has become such a well-known phrase that air purifier manufacturers keep making them to capitalize on that. They know what people have grown used to and they expect air purifiers to have HEPA filters now.

And, since people have grown so used to them, industries have continued developing those. These same people have continued improving the HEPA filter design and they’ve made several newer iterations of them over the years. These new HEPA filter iterations (or more accurately different levels) include the following, which I’ve put into a table for easy reference. The data below is taken from Medifyair and breathequality.

HEPA Filter LevelCommonly CalledEfficiency for .1 micron
HEPA 10True HEPA85%
HEPA 11True HEPA95%
HEPA 12True HEPA99.5%
HEPA 13Medical Grade HEPA99.95%
HEPA 12Medical Grade HEPA99.995%

Two “types” of HEPA filters that are out there but that aren’t actually “HEPA” filters include filters that claim to be “HEPA Like” or “HEPA Type”. Both of these air filter types aren’t actually HEPA. The companies using that verbiage are just trying to capitalize on the public’s familiarity with the phrase “HEPA”.

Now, you can’t always find the level of HEPA filter that you want in the air purifier that you’re looking at, so I’ll just tell you right here and right now that HEPA filters of all levels are great. You don’t necessarily need the highest level one, unless of course if you have medical reasons for it. For the average consumer, the higher levels aren’t nearly as important.

That’s all I’ve got for this article, today. As I’ve said before, there’s a whole lot to know about air purifiers. If you’re ready to shop for some True HEPA filters, then you can click here and shop for them on Amazon right now. Or, if you’d rather shop for medical-grade air purifiers, you can shop on Amazon here.

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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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