What is a Water Air Purifier? | The Benefits and Drawbacks of Water-Based Air Purifiers Compared to Traditional Air Purifiers


If you’ve been shopping around for an air purifier, then odds are you’ve seen a bunch of different kinds. Some with ionizers, ozone, HEPA filters, carbon, and a lot more.

But you might have not seen any water-based air purifiers (and if you did, then odds are you’re very curious about what they are).

Well, I was curious about them too, so I bought one, tested it, and fell in love.

But, before I go on, let me quickly address the big question: what are water air purifiers?

Water air purifiers are a type of air purifier that utilizes nothing but water as its means of filtering the air. Water-based air purifiers can cleanse the air of allergens like dust, dander, pollen, and much more. They can also work as an essential oil or aroma diffuser and a light humidifier.

Now that you know what water-based air purifiers are generally, let me unload a little more info on you: water air purifiers go by quite a few names, and you’ve seen me use several of them already. Those names include water-based air purifier, water air purifier, air revitalizer, water air cleaner, and a lot more terms that just mix those words around. Don’t worry, they’re all the same thing.

And, while I’m explaining things, let me tell you what traditional air purifiers are, just to make sure that you’re up to speed before I dive in too deep.

Most traditional air purifiers use something called a mechanical filter in order to clean the air in the room around them. They do this by passing the ambient air through a filter, commonly a HEPA filter in the more effective air purifiers, and this removes particles and pollutants from the air.

True HEPA filters can capture at least 99.97% of particles .3 microns and larger, for the record. And, if you’d like to read up more on HEPA filters, you can do so here.

With all of that now said, onto the next bit of this post: the comparison between air purifiers and water-based air purifiers.

What’s the Difference Between Water-Based Air Purifiers and Traditional Air Purifiers?

As I’ve already outlined, the key difference between a water-based air purifier and the other air purifiers you’ll see is that water air purifiers use water. (Shocker, I know. Hahaha)

Besides that, there are a lot of similarities in how these machines run. They both use a fan to pull the air from around the room through their filters. They both use the wind generated by that same fan to shoot the now clean air out of the room. They both do this endlessly and ensure that the air is cleaner than it would have otherwise been.

But there are more differences than just what these two kinds of air purifiers use as their filters. Sure, they do have their similarities, but they are two very distinct creations.

Here’s a little table where I compare and contrast water air purifiers with traditional air purifiers:

Characteristics of the Machine:Water Air PurifierTraditional Air Purifier
Overall Air Cleaning EfficiencyMedium-HighVery High
Efficiency at Removing Particles .3 Microns in SizeLow-MediumVery High
Efficiency at Removing Particles 10 Microns and LargerHighVery High
Cost Per Unit*25-60 Dollars (US)40-400 Dollars (US)
Oil/Aroma DiffuserYesUsually No**
Silent or Quiet OperationYesYes
Odor RemovalYesYes
Potential for Mold and Bacterial GrowthHighLow
Need for Cleaning/Filter ReplacementOnce Every 1-2 WeeksOnce Every 6-12 Months
Table detailing the similarities and differences between water-based air cleaners and traditional air purifiers

*This cost per unit basis is based on 2022 prices for comparable air purifiers made for similarly sized rooms (rooms between about 150 and 350 square feet). These numbers also cut out the outliers.

**There are some air purifiers that have the ability to diffuse oils and aromas. One such unit is made by Levoit, and it is the basis for a lot of the comparisons in this article. More on that air purifier later.

Want to see more pros and cons of water-based air purifiers? I’ve got a whole piece on just that! Check it out here: What is a Water Based Air Purifier? | The Pros & Cons of Water Air Revitalizers.

Why Are Traditional Air Purifiers Better at Cleaning the Air Than Water Air Purifiers?

While water air purifiers are good at cleansing the air of larger pollutants and even very fine dust, they aren’t nearly as effective as air purifiers that have HEPA filters. This boils down to how HEPA filters are made and how they are designed.

Long story short, HEPA filters are specifically made to clean even the smallest particles out of the air–all the way down to .3 microns, which is the size of a large virus! Because they’re made to catch such small things, they’re great at capturing larger things too.

But, as I said already, water-based air cleaners aren’t “bad” at cleaning the air–far from it. They’re pretty amazing and it’s all thanks to how water is actually sticky when it comes to things on a molecular level. Thanks to water’s stickiness it can grab onto dust and other particles and waterlog them, taking them out of the air.

If you’d like to read up some more on how well water-based air purifiers work, check out this article here!

Why Are Water Air Cleaners More Affordable Than Traditional Air Purifiers?

While both traditional and water-based air purifiers both have fans and filters and a bunch of other similar parts, traditional air purifiers still tend to be more complex. A lot of them have several different settings, some will have sensors, they’ll have lots of programming, and finally, traditional air purifiers have their main filters.

All of those things come at a cost and those costs stack up, which is one of the reasons why air purifiers with HEPA filters will cost a bit more (or a whole lot more in some cases).

Water air purifiers, on the other hand, are a lot lighter to ship, usually are a lot smaller (check out the size comparison), and are often designed to be a lot simpler.

But, at the end of the day, part of your cost savings–usually a good part of it–comes from the fact that water air cleaners don’t have expensive HEPA filters that add to their overall cost.

Their filter is just something that you can get straight from your sink!

So, in addition to being cheaper up front, water-based air purifiers can also be cheaper to operate in the long run, since you won’t have to buy replacement HEPA filters. (But there are some traditional air purifiers, like the Levoit one I’ve mentioned already, that you can clean the filter of and save money. That’s worth mentioning.)

Similarities Between Traditional Air Purifiers and Water-Based Air Purifiers Further Explained

While air purifiers with HEPA filters are better at cleaning the air than their water-based counterparts, the number of similarities between the units is still rather high.

And, spoiler alert, I personally buy both traditional and water-based air purifiers because I like them both and can appreciate the clean air they both grant me. I mention that just to tell you that I’m not jaded here. (And I must add that I’m not trying to sell you a few-hundred dollar unit like a lot of the blogs out there that trash on water-based air cleaners!)

1. Both Clean the Air Very Well

While water isn’t as effective at capturing the smallest particles that HEPA filters can get, it still does a great job at cleaning the air of most of the things people want gone. Allergens, dust, and stuff like that don’t stand a chance against a water-based air cleaner. And no, those pollutants don’t stand a chance against a HEPA filter either.

But, since we’re talking about those larger pollutants that are in your home’s air, I think it’s time I mention something important: particles as small as .3 microns aren’t usually something people worry about. Unless there’s some big sickness going on out there, or someone has some other reason to clean the air down to particles that small, most people are happy with a simple reduction of the amount of dust in their home’s air.

Why do I make this point?

Well, there are people out there that say air purifiers with HEPA filters are overkill. They say this because hospitals use HEPA filters in operating rooms and that most people probably don’t need their air quite as clean as what you see in an operating room.

And, admittedly, they’re right.

However, I’m personally fond of extra-clean air. I think it’s pretty cool that I can get air that clean and, when you are looking at the cheaper air purifiers with HEPA filters, it’s pretty easy to sell yourself on the idea.

Sure, water-based air purifiers are cheaper than traditional air purifiers with HEPA filters, but maybe it’s worth spending a few dollars more to get even cleaner air?

Or maybe it’s not.

Maybe a water air cleaner is everything you want and need. After all, air purifiers can’t add humidity to a room, they actually dry the air out a bit. Additionally, most traditional air purifiers don’t allow you to use them as an essential oil diffuser, whereas most every water-based air purifier does. If that’s something you want, then maybe a water-based air revitalizer is for you.

At the end of the day, it’s really up to you and what you want in your home. If clean air, essential oils, and humidity are important to you, then a water-based air purifier will be the perfect fit for you. Or if really clean air is what matters more to you, then a traditional air purifier will be your best bet.

Read on to see my particular recommendations for both units–not all air purifiers are made the same!

2. Both Are Great for Bedrooms

Both water-based air purifiers and traditional air purifiers with HEPA filters are great for bedrooms.

They both run quiet enough to allow you to sleep (but water-based air cleaners are often a smidge louder). They can both make enough white noise to help you stay asleep (the fact water-based units are louder makes them a bit better for this). They both clean the air which is proven to help people sleep (source: sleep.com).

However, there are some things that are worth noting:

  1. Cheap air purifiers (both traditional and water-based) can be loud and make it hard to sleep.
  2. Cheap air purifiers (of both kinds) can have high bright lights on them, making it harder to sleep with them nearby.
  3. If you want to sleep with a water-based air purifier in your room, be sure to top off the water. They can run dry if it’s been a while, and that means they can’t clean the air!
  4. A dirty water-based air purifier can become home to mold and bacteria, be sure to clean it! (Here’s an article where I tell you how to clean a water air cleaner.)

With that tidbit about making sure your water is topped off said, I’m sure you might have a couple of related questions that are answered in this article: How Often Should I Change the Water in a Water-Based Air Purifier?

3. Both Have Very Affordable Options

There are quite a few great bargains out there for both types of air purifiers, which is nice for people who want to test the waters and don’t want to spend a lot of money doing so. After all, it’s hard to commit a few hundred dollars to something that you might not be convinced you need just yet–that can wait until you try out your first machine and fall in love!

But, with that now said, I must point out that there are some seriously expensive traditional air purifiers out there–I’ve seen some for several thousand dollars! And no, I have not yet bought any of those to test or use, and I’m the one who’s a professional air purifier blogger/expert here! Because of that, I’ve never recommended such a unit, nor will I until I have tested one.

Now, with that out of the way, let me say that the bulk of the air purifiers that I have tested are on the lower end of the cost spectrum. After all, that’s what most first-time air purifier buyers will be interested in!

And, since I’ve done that, I can confidently say that there are some absolutely amazing air purifiers out there that are very affordable and work great. I expected machines that were cheaply made and (with several exceptions) I was proven wrong. These entry-level air purifiers of both types can work great and they’ll last for years.

And, on the subject of air purifiers lasting, I actually had my first air purifier develop a problem after three years. This particular one cost me $20 back when I got it and I have been very pleased with it. And yes, you saw that right, I got a great air purifier for just 20 bucks.

Unfortunately, that air purifier has a tendency to sell out often, but I still recommend it often.

And yes, I know that $20 is less than the $40 I said traditional air purifiers start at, but this one is an outlier so I didn’t include it in that data set.

Also, while I’m talking about that air purifier, here’s a link to my list of the best traditional air purifiers with HEPA filters where you can check it out. And if you’d rather look at water-based air purifiers, here’s my list of top picks for water-based air purifiers there!

4. Both Can Double As Essential Oil and Aroma Diffusers

Both traditional air purifiers and water-based air purifiers can double as essential oil diffusers. however, that comes with a big caveat–not every traditional air purifier is supposed to have essential oils used on it. In fact, most don’t allow for it–I’d go as far as to say 99% of them!

One of the very few traditional air purifiers that I know of that allows you to add essential oils to it is the Levoit one that I’ve talked about several times now. And, interestingly enough, you can’t do this with other Levoit air purifiers, it’s just this one that has the essential oil “sponge” that you add your oils to.

That sponge is in a secret compartment on the top of the air purifier.

And that leads me to an important point, the essential oil sponge on this unit is separate from the main HEPA filter. That’s important because you aren’t supposed to add ANY essential oils to the HEPA filter in any air purifier ever. Why? Well, it’ll ruin the filter and make it so it doesn’t last as long. So, please, don’t add any essential oils to anything that isn’t supposed to have it.

Now that that’s out of the way, I can talk about water-based air purifiers.

As far as I know, every water air purifier out there allows you to add essential oils to the water basin, and that’s basically the end of the story on how you use the water air purifier as an essential oil diffuser, it’s really simple.

Word of the wise, add a few more drops than you normally would add to an oil diffuser. The water basin on the water air purifiers holds a lot of water, so that dilutes things a bit.

But Which One is Better Overall?

At the end of the day, it’s really up to you on which air purifier type you prefer. As I’ve mentioned already, I personally own both types. I usually use my traditional air purifier with a HEPA filter more often since it’s easier to maintain (I don’t have to clean it as often), but I still whip out the water air cleaner when I want to.

Honestly, I think it’s hard to say which air purifier is better overall, but I will say that traditional air purifiers with their HEPA filters are better at cleaning the air, which might be the only thing that you’re concerned about with your air purifier.

However, as I said before, water-based air purifiers do a lot more than just clean the air. Those extras might make buying a water-based air purifier the go-to choice for you.

For me, I own a lot more traditional air purifiers than water-based units. That’s for many reasons, but the main one is that I like the ultra-clean air that HEPA filters provide. I do love water-based units, but the super clean air and the easier maintenance for traditional air purifiers is what does it for me.

But, at the end of the day, what you buy is your call. It all depends on what you want and need, not what I want.

However, if you’re ready to make a purchase, just know that there’s a lot of stuff that you can get lost in. I’m a pro and I get lost in the weeds on some of the air purifiers out there. So, since it can be confusing, I recommend you check out my list of all-time favorites for both water-based air purifiers and traditional air purifiers.

To see my list of recommended water-based air purifiers, visit this article.

To see my list of recommended traditional air purifiers, visit this article.

Any air purifiers that you buy through those links helps me keep this site going, which is much appreciated! So, thanks in advance, and thanks for the read today!

P.S. Here’s a related article that I wanted to link to but couldn’t find a good spot to include in the main article: What Does a Water Air Purifier Do? | The Surprising Benefits of Using Water as an Air 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.

Recent Posts