Are you trying to find out what the difference is between a HEPA air purifier vs ionizer (or ionic air purifier)?

While both products clean the air from impurities, they operate in two completely different ways.

Depending on why you want to get a home air cleaner in the first place, will determine if you should get a HEPA air purifying device or ionizer.

So keep reading to find out what each type of product does and how it purifies the air.

Air Purifier vs Ionizer

Air purifier vs ionizer

A HEPA air purifier operates by sucking air into the device through a dense, physical filter that traps airborne contaminants like dust, allergens, mold spores, bacteria, and smoke. An ionizer operates by sending out electrically charged ions into the air that bond with harmful impurities.

That’s the basic idea behind what do HEPA filters do on an air purifier and how does an air ionizer work to clean the air. But the science behind these two technologies goes much deeper as we’ll explain next.

HEPA Air Purifier

A HEPA air purifier uses a fan to draw air into the unit. It traps particles inside a dense filter and then pushes out clean, fresh air into the room.

This process continually repeats while the product is turned on and keeps the room free from contaminants.

If new impurities enter the room, like smoke or dust, the device will eventually pull these particles into the filter and prevent them from returning to the air.

That’s what makes a HEPA filter the best air filter for allergies, the best air filter for asthma, and the best air filter for mold. In fact, the highest-grade HEPA filter can trap 99.97% of particles down to 0.3 microns in size, giving you peace of mind that the most harmful contaminants are being removed from the air you breathe.


The process behind how an ionizer works is that it sends out electrically charged ions into the air that bond with harmful impurities. And once a bond is made, these particles become too heavy to stay in the air.

This results in the contaminants falling onto the floor or sticking to surrounding surfaces.

Ionizers can attack finer particles than HEPA filters; down to 0.1 microns. But keep in mind that there’s always a chance that the particles can be stirred back up into the air again when people or pets walk through the room or touch a surface.

This can result in a constant cycle of impurities being removed from the air and then returning back to it because the particles are not technically removed from the room. This is one of the reasons why we don’t suggest ionizers for people with respiratory conditions like asthma (i.e. the particles are not collected). You can learn more about this topic on our ionizers and asthma page.

As you can see, the major advantage that a HEPA air purifier vs Ionizer has is that the HEPA unit actually traps the airborne contaminants and stops them from reentering the air you breathe.

See all of Amazon's Best Selling Air Purifiers

Ionic Air Purifier vs HEPA Air Purifier

Ionic air purifier vs HEPA

An ionic air purifier uses a fan to draw air into the unit. The air passes by a set of electrically charged plates. Electrostatic attraction occurs and the pollutants stick to the plates. This is different than a HEPA filter that traps particles in a mesh filter.

The main difference between an ionic air purifier vs HEPA air purifier is that the electrostatic collection plates can be washed and reused as they become dirty. On a HEPA air purifier, the HEPA filter must be replaced when it becomes clogged.

Also, HEPA air purifiers are more efficient at capturing pollutants even as they’re getting dirty. That’s because the material is a collection of interwoven fibers that is thicker and denser.

On an ionic air purifier, when the metal plates become dirty, the particles can pass through the system because the electrically charged surface of the plates is covered by other pollutants. That’s why routine cleaning is necessary for maximum effectiveness.

Additionally, the process of electrically charging the metal plates can produce small levels of ozone as a by-product. The same thing is true for the technology in ionizers that emit charged ions into the air. But for the most, ionizers and ionic air purifiers are safe for people to be around as explained in our article, “are ionizers safe?”

What you need to know here is that some people with respiratory conditions can experience lung irritation from ionizers and ionic air purifiers that produce ozone in trace amounts even though research reveals that “no data showed the harmful effects of NAIs [negative air ions] on humans/animals.”

So if you have health conditions like asthma, COPD, bronchitis, or emphysema, then you should choose a HEPA air filter purifier as these units produce zero side effects. And if you were wondering at all, can air purifiers make you sick in any other way (i.e. sore throat, cough, or nosebleed), the answer is no.

Difference in Maximum Area Coverage

Because a HEPA air purifier uses a physical filter, the maximum area it can cover is typically not as large as an ionizer.

In fact, the largest room size an air purifier with a HEPA filter can effectively purify that we’ve seen for sale is 1,560 sq. ft., called the AIRMEGA 400.

This is fine for most home applications, but for a large business space it may not be sufficient.

To find out if this particular air purifier will work for you, visit our top 10 air purifiers page to read more about it.

As a comparison, we’ve seen some ionizers that purify an air space up to 3,500 sq. ft. That’s a huge amount of coverage and can clean the air of even the largest home or business.

As for ionic air purifiers that use a metal filter to trap pollutants, these units tend to max out at 500 sq. ft. That’s because an ionic air purifier requires a fan to draw the air through the system and the electrostatic collection rods can only be so large.

The Envion Ionic Pro is a good ionic air purifier for home use. You can find out if this is a better choice for you by visiting our best ionic air purifier reviews page to see all the details on this product.

We also have a page that helps you figure out how big of an air purifier do I need. So give it a look if you’re not sure what size to get.

Initial Cost vs Annual Maintenance Costs

In many ways, a HEPA filter air purifier is a more advanced technology, but it does come with a cost.

In fact, good HEPA air purifiers are almost always more expensive than ionizers and ionic air purifiers.

For example, there are some ionizer air purifiers for sale that cost as little as $50. The cheapest HEPA filter air purifier we’ve ever found that’s worth the investment is around $100. So you’ll have to spend more money to get a HEPA air purifying device.

That being said, a HEPA air purifier also costs more to maintain unless you get an air purifier with a washable filter. Those units have no annual maintenance costs.

Because HEPA air purifiers use a physical filter, it needs to be replaced on regular basis. This can range from 6 months to one year or more. As the filter collects contaminants, it gets dirty and clogged up. And the more pollutants it traps, the less efficient it is at cleaning the air.

Ionizers don’t use filters at all and ionic air purifiers have metal collection rods or plates that can be wiped clean. Therefore, you don’t have any yearly maintenance costs in regards to filter replacements with these types of units.

Now you may be wondering, “is an air purifier worth it?” The answer is yes because HEPA air filters are much more efficient than ionizers and ionic air purifiers are trapping pollutants. Experts agree that ionizers and ionic air purifiers are a good budget option to get a general level of clean air in the home; however, HEPA air purifiers are the top choice for superior air cleaning and protection for health. You can read more air purifier health benefits here.

But regardless of the type of air cleaner you choose, research indicates that “reduction in particulate matter and allergens results in reducing symptoms and in certain cases, preventing disease progression across all age groups, including the elderly and children. The evidence is apparent, in chronic respiratory diseases, such as asthma and in cardiovascular health.” Also, “Technologically advanced air filter systems are now available which efficiently remove particulate matter, resulting in significant health benefits to patients of asthma and cardiovascular disease.”

Design and Style Options

Finally, the design and style options are very limited in ionizers.

What you’ll mostly find are thin vertical units that can be placed in a corner or small compact square-shaped units that can be placed practically anywhere.

Most ionizers and ionic air purifiers have a modern design and some are futuristic looking. And all of the ones we have reviewed must sit on the ground or on a table. We have never seen a wall-mountable product.

HEPA air purifiers, on the other hand, come in all shapes and sizes.

You can find a product that matches the décor of your room if you look hard enough. Some products are wall mountable too, which means you can place them practically anywhere inside your home or business. The air purifier company, Rabbit Air, makes a good unit like this that is highly acclaimed.

You’ll also find a variety of colors and styles with HEPA air purifiers. There are many more options available to you as a consumer than compared to ionizers.

If you need more help on picking an air purifier for your home, then we recommend you read our how to choose an air purifier guide. It explains every aspect of air purifiers, ionizers, and ionic air purifiers

Air Ionizer vs Air Purifier Summary

We hope you enjoyed this guide on the difference between a HEPA air purifier vs ionizer.

As you learned, a HEPA air purifier can be more efficient at removing pollutants from the air because it actually traps the particles inside a physical filter. An ionizer, on the other hand, doesn’t remove the contaminants but causes them to drop out of the air you breathe.

In regards to an ionic air purifier vs HEPA air purifier, the ionic air purifier works similar to a HEPA air purifier but it uses electrically charges plates to collect the pollutants. These metal plates can be washed and reused as the pollutants fill them up. This makes ionic air purifiers a more cost-effective solution than a HEPA air purifier; however, they’re not as efficient as a HEPA filter when it comes to the total square footage coverage.

Avatar for David Morrison

About David Morrison

David is an Air Quality & Comfort Technician. He has expert knowledge on the technology and design of air purification, air conditioning, and heating systems. His main role is to write content that helps people get the most value out of their air purifiers, air conditioners, and heating units. (See Full Bio)