Reviews You Can Rely On

Best Aromatherapy Diffuser of 2021

We tested a variety of aromatherapy diffusers from brands like Raindrop, Vitruvi, and more, to determine which diffused oil the best
We tested a wide array of diffuser types and styles.
Credit: Maggie Brandenburg
By Maggie Brandenburg ⋅ Review Editor  ⋅  Aug 3, 2021
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more
After researching dozens of the best essential oil diffusers, we chose the top 12 most promising models to test side by side. We practically bathed in a finely scented mist to put each of them through their paces and find the best. We tested their coverage and consistency, cycled through every setting, and measured how long they'll last before running out of water. Whether you want a strong cloud to bask in, a light fragrance to accent your home, or a humidifying nightlight to calm you to sleep, we've found the perfect diffuser for your domain and your wallet.


1

Best Overall Aromatherapy Diffuser


ASAKUKI Smart Wi-Fi 700ml


Type: Ultrasonic | Measured Run Time: 48 hours
Huge capacity
Very long run time
Extremely easy to use with app
Limited functionality without app
Perhaps too powerful for small spaces

If you're after a diffuser that can fill a whole floor and will keep running for a long time, you've found it. The ASAKUKI Smart diffuser is a ready for action and has the largest capacity of any unit we tested. By connecting to your home WiFi network, the ASAKUKI is easily controlled by a free app, TuyaSmart. It takes just a few minutes to get started, and then you can control your diffuser from anywhere in the house. The unit itself has the same standard, minimal buttons as many other models, but impressive control through the app. Select your favorite color from the entire spectrum, choose your brightness on a sliding scale from 0-100, and easily change the mist's strength coming out the top. You can even set up specific schedules and pair with your Alexa-enabled device to turn on your favorite diffuser mood with just your voice.

Without the app, the ASAKUKI settings work much like many other diffusers we tested. Its most significant selling point is the additional and exceptional control you have harnessing the power of today's smart technology. And though we love its thick plume of fragrant mist that can last all weekend, for small spaces, it can be a bit much. It also isn't the most chic-looking model in the line-up, but it's also not our least favorite — woodgrain accents help the ASUKAKI fit in better around your home. For the best coverage, longest run time, by far the most control, and the sheer ease of integrating this device into your smart home, this diffuser takes the proverbial cake.

Capacity: 700ml
Timer Settings: 1 hour, 3 hours, 6 hours, ON (auto shut off when empty)
Mist Settings: Weak, strong

Includes: Diffuser, adapter, directions, 150 ml measuring cup, optional free app, optional Alexa-enabled voice control

The ASAKUKI is an exceptionally long-running diffuser that's easy to...
The ASAKUKI is an exceptionally long-running diffuser that's easy to control with an app or through Alexa.
Credit: Maggie Brandenburg

2

Best Bang for Your Buck


RENWER 500ml with Remote


Type: Ultrasonic | Measured Run Time: 18 hours
High capacity despite small size
Comes with a remote (and battery)
Easy to clean
A bit loud
Timer options are short

The RENWER 500ml is an obvious choice for every scent-seeking, remote-lover out there. This aromatherapy diffuser is impressively compact for its capacity and is the smallest 500ml unit we tested. It's a fairly standard design that's simple to use and easy to clean, offering solid spatial coverage and average run time, all for half the price of many competitors. Like much of the competition, it provides seven colors that you can choose on bright or dim modes, or you can cycle through the whole spectrum. The entire top lights up, making for a relatively bright spot in a dark room. The remote not only allows you to control the unit from across your abode but also offers an option for an intermittent mist that isn't available with the on-unit buttons alone.

While we don't think this diffuser is excessively loud, it is one of the noisier specimens we tested. It hums like a small fan and makes the typical bubbling and glurping noises of an ultrasonic diffuser. It's not unpleasant, but could be a bit much if kept on your bedside table. It also only has timer options of 1, 2, and 3 hours, which we find somewhat limiting compared to most others that can be set to last through a full workday or night of sleep. Dispite these shortcomings, we still think the RENWER is a solid performer and a great value for the price.

Capacity: 500ml
Timer Settings: 1 hour, 2 hours, 3 hours, ON (auto shut off when empty)
Mist Settings: Low, high

Includes: Diffuser, adapter, directions, 150 ml measuring cup, remote (with battery)

Smaller than the other 500ml diffusers, the RENWER comes with a...
Smaller than the other 500ml diffusers, the RENWER comes with a super handy remote (and battery!) all for a lower price than you might think.
Credit: Maggie Brandenburg

3

Best Nebulizing Diffuser


Raindrop 3.0 Nebulizing Diffuser


Type: Nebulizing | Measured Run Time: 2 hours
Pure, effective coverage
Quiet and elegant
Just enough features
Limited settings options
Short run time

The Raindrop 3.0 is our favorite nebulizing model we tested. This type of diffuser creates pure atomized oils not diluted by water. This elegant glass-topped unit looks great anywhere, with clean, smooth lines, and it's mesmerizing to watch the essential oil vaporizing within and rising slowly out the top. Without the need to dilute your oils, the Raindrop 3.0 quickly fills your space with pure scent, easily covering large rooms without the extra humidity created by ultrasonic devices. This classy-looking diffuser is quiet even on its highest setting and features a simple white LED light and a built-in 2-hour timer. It runs in a cycle of 2 minutes on and 1 minute off to provide even, effective coverage. It's also the only model we tested with a magnetically attached cord to help prevent a disaster if you trip over the cord — though it's not foolproof.

However, if you love bells and whistles, the Raindrop 3.0 may seem a little bare-bones. You can choose to have the small white light on or off, and the dial will select your preferred aroma intensity, but that's the extent of it. This attractive little unit will run for its programmed cycle for 2 hours before shutting off (though the light remains on). While we initially considered this a downside, we quickly discovered that the Raindrop is so effective that having it on for more than 2 hours at a time can be overpowering. If you're on the prowl for a simply designed diffuser that offers excellent coverage of pure scent, we think this tasteful model is well worth its price.

Capacity: N/A
Timer Settings: Runs for 2 hours no matter what
Mist Settings: On for 2 minutes, off for 1 minute; intensity dial

Includes: Diffuser, adapter, directions, 2 plastic pipettes, glass pipette

The Raindrop 3.0 is an effective unit, easily filling even large...
The Raindrop 3.0 is an effective unit, easily filling even large spaces with pure oil aromas - and it looks great, too.
Credit: Maggie Brandenburg

4

Best for Consistent Coverage


Anjou 500ml


Type: Ultrasonic | Measured Run Time: 30 hours
Unique oil tube more evenly dispenses scents
Long run time
Subtle light ring
Very large
Inner lid is difficult to clean

The Anjou 500ml is the answer if you're looking for subtlety and consistency. This teardrop-shaped aromatherapy diffuser comes with a unique oil tube inside to distribute essential oils more evenly over time. Most other models let the oil float on top, where it tends to be diffused first, initially packing a powerful punch but growing weaker the longer the unit runs. By adding your oils to the small glass tube inside, the Anjou evaporates a smaller but more consistent amount of oil throughout its exceptionally long run time. It may take longer before you smell it, but the delicate fragrance lasts longer than most others. It's also one of the few models with a visible difference between the high and low mist settings — many others appear identical in output. A thin light ring wraps around the base's middle, providing an understated accent color that won't blind you in your bedroom at night.

However, this diffuser is rather large. The Anjou is enormous compared to others we tested with similar or even larger capacities. Be sure you like the look of whichever color or woodgrain you decide to purchase, as it isn't something easily tucked away out of sight. The inside portion of the lid also has a lot of very complicated surface area that makes it more challenging than most to clean when you want to swap between scents. And because it prioritizes a slower, more even use of oils, it does take longer to fill your space with that fresh scent. However, the Anjou is an excellent choice to keep your quarters pleasantly refreshing for hours on end if you're after consistency and don't mind the size of this centerpiece.

Capacity: 500ml
Timer Settings: 1 hour, 4 hours, 8 hours, ON (auto shut off when empty)
Mist Settings: Low, high

Includes: Diffuser, adapter, directions, small cleaning brush, extra essential oil tube

Though it's quite large, the Anjou provides the most consistent...
Though it's quite large, the Anjou provides the most consistent coverage throughout its exceptionally long run time.
Credit: Maggie Brandenburg

5

Best for Accident-Prone Households


InnoGear 200ml Woodgrain


Type: Ultrasonic | Measured Run Time: 15 hours
Hard to knock over
Straightforward to clean
Solid run time for capacity
Beeps when timer is done
Max fill line is less than half the tank

The maker of several types and sizes of diffusers, InnoGear, is also behind this little 200ml Woodgrain model that we grew to love during testing. This unassuming, moderately sized aromatherapy diffuser keeps its smaller capacity wide and low, making it very difficult to knock over. Despite having a volume of less than half of many others, it still manages to pump out therapeutic mist for nearly as long. Its simple shape also makes it very easy to clean regularly without a huge hassle. Additionally, the woodgrain exterior with a thin light strip helps it to more easily blend into your decor without sticking out like a sore thumb.

We find it odd that the maximum fill line inside the tank is well under half its actual capacity. The actual capacity turned out to be around 500ml, but the directions clearly state not to exceed that lower fill line of just 200ml, for some reason. The only real complaint we have about this solid performer is that it beeps rather loudly when the timer shuts off, which isn't ideal for a bedroom at night. However, the InnoGear 200ml Woodgrain is sure to help keep your essential oils off the counter if you live in a house where things often get knocked over or spilled.

Capacity: 200ml
Timer Settings: 1 hour, 3 hours, 6 hours, ON (auto shut off when empty)
Mist Settings: Low, strong

Includes: Diffuser, adapter, directions

In a house full of clumsy people and a large, tail-wagging dog, the...
In a house full of clumsy people and a large, tail-wagging dog, the extra stability and low center of gravity of the InnoGear 200ml Woodgrain are much appreciated.
Credit: Maggie Brandenburg

6

Best for Classy Appearances


Vitruvi Stone Diffuser


Type: Ultrasonic | Measured Run Time: 7.5 hours
Ceramic cover looks fantastic
Painless to clean
Decent coverage
Very limited settings
Ceramic top needs extra care

The Vitruvi Stone Diffuser is small, but absolutely gorgeous. Unfortunately, this elegant diffuser has a tiny 90ml capacity and minimal settings. Depending on how you dilute your oils, you can still get pretty good coverage, it just won't be able to tackle your entire 2000 square foot house. Still, it filled our main tester's spacious living and dining room area with relative ease. Limited timer and light settings keep it simple to use and looking fly in the process. It's even uncomplicated to clean; simply run it for 30 minutes with a specified white vinegar mixture, and you're good to go.

However, the Vitruvi will likely disappoint if you're looking for a rainbow of color options or a plethora of timers and mist settings. It's narrow band of light has only one color (a peachy orange shade) of a single brightness. And it offers only two usage settings with no option to just turn it ON and walk away. The ceramic stone top is also much easier to break, scratch, or even get fingerprinted than the plastic tops of most other diffusers we tested. And the cap on the reservoir has a pointy top where the mist escapes that needs to be carefully lined up with the hole in the ceramic cover. Still, we think it's a great addition to a single room where you can WOW your friends and family with its fresh looks and bouquet.

Capacity: 90ml
Timer Settings: 3 hours (continuous mist) or 7.5 hours (intermittent mist)
Mist Settings: Intermittent (30 seconds on, 30 seconds off; 3 hours only) or continuous (7.5 hours only)

Includes: Diffuser, adapter, directions, 200 ml measuring cup

We can't get enough of the matte ceramic finish of the Vitruvi...
We can't get enough of the matte ceramic finish of the Vitruvi, which makes a great office companion.
Credit: Maggie Brandenburg

7

Great Options for Glass and Wood Elegance


ArOmis Waterless Nebulizer


Type: Nebulizing | Measured Run Time: 4 hours
Potent coverage
Simple to use
Looks fantastic
Very limited settings and features
Vibrates rather noisily

There's much to love about the wood grain base and delicate glass top of the ArOmis Waterless Nebulizer — and plenty of options to match your style of decor. This nebulizing diffuser atomizes pure essential oils, offering fast-acting, room-filling scents that ultrasonic units just can't keep up with. Cutting down on some of the extravagances of other models, the ArOmis operates with a single dial, allowing you to adjust your preferred intensity while all other settings remain consistent. Though it's a touch smaller than we had envisioned before buying, we love how it looks just about anywhere around the house, easily filling even the largest spaces with our favorite fragrances.

If you're hoping for timer options and lights, you'll want to look elsewhere, because the ArOmis has neither. Units run for a specified length of time (ours was 4 hours, but other durations are available) in cycles of 10 minutes on and 10 minutes off. In small spaces, this can be a bit overpowering, but it is certainly effective. Our main grip is how loud is it. Even on its lowest intensity setting, the vibrations are clearly audible, regardless if we set it on a wooden desk or directly on a carpeted floor. Its highest setting is difficult to ignore unless it was on the other side of a large room with other sounds masking its hum. If you don't mind some white noise and need a diffuser with a super potent output, the stylishness of this small, sophisticated nebulizing diffuser is sure to add some tasteful flair — and aroma — to your space.

Capacity: N/A
Timer Settings: 4 hours (can also purchase units that run for 1 hour, 8 hours, or 12 hours)
Mist Settings: On for 10 minutes, off for 10 minutes; intensity dial

Includes: Diffuser, adapter, directions, plastic pipette

The ArOmis nebulizing diffuser is small but extremely potent and...
The ArOmis nebulizing diffuser is small but extremely potent and with looks we love.
Credit: Maggie Brandenburg

8

Super Handy Timer Buttons


Homàsy Ultrasonic


Type: Ultrasonic | Measured Run Time: 40 hours
Super easy timer buttons
Long run time
Solid coverage
Limited light options
Rather noisy

Created to keep running for a long time, the Homàsy Ultrasonic is a good-sized diffuser. During our testing, this 500ml unit was outlasted only by one model with an even larger capacity. It's a good choice for covering larger spaces and is even advertised as a limited humidifier when used without essential oils. While most models we tested have several timer options you can cycle through, only the Homàsy has separate buttons to quickly select whatever amount of time you want it to run. You can also quickly change it to sleep mode, which changes the unit to low mist and turns off the light with a single press of a button. If you'd rather have a bright nightlight, you can turn on whatever color you elect to drift off to dreamland with.

Unfortunately, this a poor choice if you prefer a dark space when you sleep, as there are no dim light options. It's a reasonably chunky package, even considering its capacity. The top is also indented, which we found collected pet hair quite readily. This shape is less conducive on the inside to regular wiping to remove oil build-up, and it's one of the loudest diffusers we tested — another reason not to keep it in your bedroom. Yet if you don't mind the mechanical hum or the choice between a bright light or no light, we do appreciate the simplicity of the buttons on the Homàsy that allow you to quickly and easily get it running the way you want.

Capacity: 500ml
Timer Settings: 1 hour, 3 hours, 6 hours, ON (auto shut off when empty)
Mist Settings: Low, high

Includes: Diffuser, adapter, directions

Obvious and easy-to-use buttons make the Homasy simple to use.
Obvious and easy-to-use buttons make the Homasy simple to use.
Credit: Maggie Brandenburg

9

Decent But Loud


InnoGear 5-in-1


Type: Ultrasonic | Measured Run Time: 18 hours
Works for large spaces
Easy to clean
Solid usability
Noisy
Short timer settings

Another offering from InnoGear that offers reliable coverage and a good-sized capacity is the InnoGear 5-in-1. This 500ml aromatherapy diffuser is a tried and true design that just works. It's a bit large but far from the largest we tested. It's simple and easy to clean and handily covers even larger rooms in your home. With standard high and low mist functions, several timer options, and seven different light colors that can be bright or dim, the 5-in-1 has plenty of ways to use it.

However, it doesn't stand out from the crowd in any way. It also has timer settings on the short end of the spectrum, though you can just turn it ON if you want it to run longer than 3 hours. The directions caution you not to let it run for longer than 10 hours at a time, though we pushed ours to 18 just to see what it could do. In doing so, we discovered this diffuser is by far the loudest of the bunch — and not with the pleasant gurgling noises of water splashing around, but instead the constant hum of a fan. It does have a pretty low comparative price tag, though, which may be its biggest selling point. The 5-in-1 is an adequate diffuser that gets the job done as long as you don't mind some extra noise.

Capacity: 500ml
Timer Settings: 1 hour, 2 hours, 3 hours, ON (auto shut off when empty)
Mist Settings: Low, high

Includes: Diffuser, adapter, directions, 150 ml measuring cup

The InnoGear 5-in-1 is easy to use and clean, though a touch loud...
The InnoGear 5-in-1 is easy to use and clean, though a touch loud for many of our testers.
Credit: Maggie Brandenburg

10

Great Gift Package


Pure Daily Care Ultrasonic Gift Set


Type: Ultrasonic | Measured Run Time: 20 hours
Woodgrain exterior
Comes with 10 essential oils
Uncomplicated to use
Only one mist option
Thin neck harder to clean

The Pure Daily Care Ultrasonic is an excellent gift idea if you're searching for the perfect starter kit to give your favorite budding essential oil enthusiast. You get a pretty woodgrain diffuser AND 10 different 10ml bottles of common essential oil for one reasonable price. Also included is a brief description of each oil and some of their common and preferred uses. An average-sized reservoir and great run-time help the Pure Daily to be a user-friendly choice. Additionally, its buttons and settings are simple to comprehend and easy to use.

For the tech hounds out there, the simplicity of the Pure Daily Care may be underwhelming. It has just one mist setting, and during our testing, the light was inconsistent in whether it turned off when the unit shut off or remained on. The thin neck is also more challenging to clean than most of the flat-topped models we tested. And the essential oils don't say if they're 100% pure or not — which is something you definitely want when putting them into your diffuser. The Pure Daily Care might not be elite enough for a hardcore essential oil enthusiast, but it's a great value package as a starter kit or gift.

Capacity: 300ml
Timer Settings: 1 hour, 3 hours, 6 hours, ON (auto shut off when empty)
Mist Settings: Continuous/one level only

Includes: Diffuser, adapter, directions, ten different 10ml bottles of essential oils

The Pure Daily Care comes with 10 essential oils, making it a great...
The Pure Daily Care comes with 10 essential oils, making it a great gift or starter kit.
Credit: Maggie Brandenburg

11

Outstanding Value for Small Spaces


URPOWER 2


Type: Ultrasonic | Measured Run Time: 6 hours
Simple and straightforward
Very quiet
Bright light is great for nyctophobia
Small capacity runs out quickly
Very limited settings

One of several lookalikes on the internet, the URPOWER 2, is a minimalistic aromatherapy diffuser that's uncomplicated to use and inexpensive. Though many claim to be "whisper-quiet," the URPOWER is genuinely an exceptionally quiet device. It has minimal options perfect for the essentialist: ON or OFF, and continuous or intermittent mist. Lacking any timers, this little machine simply runs until it's empty, which is around 6 hours using the intermittent setting. The entire translucent device lights up brightly or dimly in seven colors, or it cycles through the rainbow, making it a solid choice for those who have nyctophobia (i.e., fear of the darkness.)

The URPOWER is best used in smaller spaces because of its limited capacity and can be an excellent fit for a child's bedroom or even your office at work. However, if you're hoping for a diffuser that can last all night or the whole workday, this isn't it. It's also not the best choice to keep your entire 4 bedroom house smelling fresh, and its limited options may be too limited for some. Additionally, it isn't the most elegant in appearance and has a surprisingly short cord — just 4 feet long. However, the URPOWER is a reliable option for an undersized, elementary model that fits in modest spaces and boasts an appealing price tag.

Capacity: 100ml
Timer Settings: ON (auto shut off when empty)
Mist Settings: Intermittent (30 seconds on, 30 seconds off) or continuous

Includes: Diffuser, adapter, directions

The strong glow of the URPOWER 2 makes it a great light for dark...
The strong glow of the URPOWER 2 makes it a great light for dark spaces.
Credit: Maggie Brandenburg

12

A Really Pretty Nightlight


EQUSUPRO Ultrasonic Cool Mist


Type: Ultrasonic | Measured Run Time: 16 hours
Vivid and mesmerizing
Several interesting patterns
Pretty good run time
Inconsistent, underwhelming performance
Sloppy design

We love the way the EQUSUPRO Ultrasonic Cool Mist seems to dance in the dark. Unfortunately, when it comes to actual diffusing performance, we found ourselves wanting more. The colors of lights in the EQUSUPRO are more vibrant than any other model we tested, giving this blackened metal unit a rich, striking appearance with the lights on or off. Five different possible patterns let you choose a design you love to look at. And for a small 100ml diffuser, we're pleased to report it kept running longer than we expected.

Unfortunately, this long run time was mostly due to the wild inconsistency of how much mist the EQUSUPRO was putting out. While at first, it was a veritable smokestack, filling the room with sweet-smelling scents, after several uses, it started unpredictably oscillating between working precisely as promised and putting out so little mist that it could barely be seen. The design could also be cleaned up a bit. You can see the end of the white reservoir funnel poking through the black metal top, ruining its sleek appearance. However, you may find a use for the EQUSUPRO if you're more interested in a cool light than its diffusing capabilities.

Capacity: 100ml
Timer Settings: ON (auto shut off when empty)
Mist Settings: Intermittent (30 seconds on, 30 seconds off) or continuous

Includes: Diffuser, adapter, directions, 150 ml measuring cup

Sleeping next to a diffuser can be very soothing, both for the added...
Sleeping next to a diffuser can be very soothing, both for the added humidity and the possible blends of oils you could use to lull yourself into a peaceful slumber.
Credit: Maggie Brandenburg

Why You Should Trust Us


This review is spearheaded by a two-headed team of testers, Maggie Brandenburg and Penney Garrett. Maggie is a Grade A gadget fiddler, always tinkering with settings and pushing the limits of every piece of tech she owns. Living with a perpetually dirty adventure dog (and partner!), she appreciates the value of a clean-smelling home and is always trying new methods of making it so. Penney studied botany and clinical herbalism and has worked in several apothecaries, selling and experimenting with a wide variety of oils. The two of these ladies have been testing products for GearLab for many years and put their heads together to prod these diffusers and find their limits.

After spending hours researching dozens of the most interesting and promising models on the market, we narrowed it down to the top 12 aromatherapy diffusers. We enthusiastically purchased them all and pitted them head to head — or nose to nose — to see which ones would come out on top. We filled them to their limits, challenged them to infuse large spaces, and ran them for days at a time. We put them all around our homes in the day and during the night to figure out where each fits best. If you've felt like every diffuser sounds the same as the last, read on! We're here to illuminate their differences and help you decide which one is the right choice for you.

Testing dilution strengths in ultrasonic models.
The many lighting options available.
Cleaning every nook and cranny.

Analysis and Test Results


To test this line-up, we didn't merely plug all the diffusers in, turn them on, and walk away. We broke down exactly what we want from an ideal diffuser and tested every aspect in detail. Our process ranged across five comprehensive and mutually exclusive metrics to provide a precise and accurate picture of each model's strengths and weaknesses. Below, we discuss how we did it and which ones excelled where.

While all these diffusers will fill your room with whatever scent...
While all these diffusers will fill your room with whatever scent you choose, they have many differences that we uncovered during our testing.
Credit: Maggie Brandenburg

Effectiveness


The most important aspect of an aromatherapy diffuser is how well it works. We considered each unit's coverage, intensity, and humidifying properties to understand their effectiveness. We scientifically tested each diffuser with identical dilutions in the same sized space to see how quickly they filled the area and if they became overpowering or were too subtle. We measured humidity changes (from ultrasonic units) and scrutinized the many different mist intensity settings.

Choosing Essential Oils
When it comes to getting the scent you want, purity matters. Choose only 100% pure essential oils to get clean, consistent fragrances from your diffuser and elongate its life. In general, pure oils tend to cost more (especially for the less common and harder to distill oils, like rose). An unusually low price often indicates diluted oils or man-made "fragrances" — a very different thing than actual distilled oils from plant material. At the very least, pure oils will say 100% pure somewhere on their label and should not say "fragrance."

Nebulizing diffusers take the cake when it comes to filling a space with pure, clean aromas in a short span of time. Because they don't require any dilution of your essential oils, they directly atomize pure oils, offering stronger scents. Though they can be overwhelming in very small spaces if left on too long, they can be a lifesaver for easily filling large rooms and quickly creating a "scent garden" wherever they are. We tested several nebulizing models. The ArOmis is one of the most potent diffusers of any kind that we tested. Its 10 minutes on, 10 minutes off cycle rapidly covers your living space with fragrance. The Raindrop 3.0 is slightly more subtle and more evenly distributed, with its 2 minutes on, 1 minute off cycle, and is our overall favorite nebulizing model.

Nebulizing aromatherapy diffusers - like the Raindrop 3.0 - provide...
Nebulizing aromatherapy diffusers - like the Raindrop 3.0 - provide far more potent aromas that are well-suited to filling large spaces in a small amount of time.
Credit: Maggie Brandenburg

Providing the most consistent coverage of any ultrasonic model we tested is the Anjou 500ml. It alone has an oil reservoir on one side of the water reservoir that evenly dispenses oil as the water level goes down. This provides a steady level of fragrance for as long as the water and oil supplies last, rather than running through all the oil floating on top of the water first, as most others tend to do. It's also one of the only models we tested where we could actually see the difference between high and low mist settings.

The Anjou covers a good-sized space and has a visible difference...
The Anjou covers a good-sized space and has a visible difference between the high and low mist settings.
Credit: Maggie Brandenburg

Also particularly effective, the ASAKUKI Smart diffuser emits a large, evident plume of mist for as long as the tank has water in it. It works very well to cover large spaces and adds humidity to the air when used in smaller rooms. The Homàsy Ultrasonic and InnoGear 5-in-1 also both provide substantial coverage for larger spaces. Their low and high mist settings are less obvious to tell the difference between looking at them, but they're great for a little humidity bump.

The InnoGear 5-in-1 has a large capacity that more easily takes on...
The InnoGear 5-in-1 has a large capacity that more easily takes on bigger spaces - like a large living room.
Credit: Maggie Brandenburg

Ease of Use


To test ease of use, we considered numerous factors, including capacity, ease and frequency of refilling, and the included directions. We navigated settings while trying to decipher cryptic direction booklets and online informational videos. We tried every combination of features and settings we could just to see what they would do. And we also accounted for the intuitiveness of each, as we're just as guilty as everyone else for throwing the instruction manual away after a few days of ownership.

Different Types of Diffusers
There are many different ways to diffuse the smell of essential oils into your home and numerous kinds of diffusers to help you. We tested mostly ultrasonic diffusers, which make ultrasonic waves in oil-treated water reservoirs to create a fine, aromatic mist that fills the air. We tested a few nebulizing or waterless diffusers, which atomize essential oils, creating a pure scent that can fill even larger spaces. There are also evaporative diffusers, which use various methods to evaporate undiluted essential oils (like electricity or a candle). You can also soak terra cotta in essential oil and hang it or put certain wood types into small essential oil vessels for a more subtle evaporative effect.

The TuyaSmart app makes controlling the ASAKUKI simple, offering...
The TuyaSmart app makes controlling the ASAKUKI simple, offering easy toggles between mist settings, programmable schedules, precise light controls, and even Alexa-integrated voice functionality.
Credit: Maggie Brandenburg

Several diffusers stand out here for different reasons. In light of their functional and straightforward added technologies, the AKASUKI and RENWER are easy to use. The RENWER comes with a small remote that's self-explanatory and does everything you want it to do. The AKASUKI is easily controlled with an app on your smartphone or by voice using your Alexa-enabled device — as long as you have a WiFi connection. Using both of these is an absolute breeze.

It's tough to get much more straightforward than the RENWER's...
It's tough to get much more straightforward than the RENWER's uncomplicated, very handy remote.
Credit: Maggie Brandenburg

The InnoGear 200ml Woodgrain is also very easy to use. It has impressively intuitive buttons, and the lid practically closes itself when you set it on the base. It's effortless to spin the vent to blow in any direction and remove the lid completely when adding more. The Anjou 500ml and Homàsy Ultrasonic are both similarly easy to open and close and have reasonably large capacities that require less frequent filling.

The EQUSUPRO has very few settings to choose from, and so is quite...
The EQUSUPRO has very few settings to choose from, and so is quite easy to use. However, you can see here that the white plastic of the inner water reservoir sticks out the top of this otherwise good-looking diffuser.
Credit: Maggie Brandenburg

A few of these aromatherapy diffusers are very simple to use due to a limited range of features. The URPOWER 2, Vitruvi Stone Diffuser, and EQUSUPRO Ultrasonic Cool Mist are very simple to operate because they lack many of the timer, mist, and/or light settings of their competitors. Additionally, all three of them have shorter cords on their adapters, forcing them to be closer to an outlet to function. The nebulizing models we tested, the Raindrop 3.0 and ArOmis, are also very straightforward, each with a simple dial to control their power and mist intensity.

The Raindrop 3.0 features a dial that controls power and allows you...
The Raindrop 3.0 features a dial that controls power and allows you to fully adjust the intensity of mist you desire. A small touch-sensitive metal pad below the dial turns the white LED light on and off.
Credit: Maggie Brandenburg

Run Time


To score each contender in this metric, we tested and measured every power function they have. From preprogrammed timers to running each until they dried out and shut off, we pushed them to their limits of continuous use. We also considered what options each has available to the consumer and how useful those time intervals and mist options are to the average user.

Adding Humidity with a Diffuser
Because ultrasonic diffusers atomize water along with essential oils, they also have a slight humidifying effect. This can be beneficial in smaller spaces - like a bedroom during the dry season. However, it can also sometimes collect on surfaces close by the diffuser, so be careful what you set your machine next to. Try to avoid putting it next to water-sensitive objects like electronics or books.

Taking home the grand prize in this metric is the ASUKAKI. As the diffuser with the largest capacity in our tests, we expected it to outlast the rest when left to run dry. However, we didn't expect it to pump out a consistent cloud for over 48 straight hours, but that's precisely what it did. That alone is incredibly impressive. Additionally, the ASUKAKI has similar timer options to many others we tested and equivalent high/low mist modes. Coming in a close second, the Homàsy Ultrasonic boasts the same timer and mist functions and a 500ml capacity that lasted over 40 continuous hours in our tests.

The Homasy has a pretty large capacity and one of the longest...
The Homasy has a pretty large capacity and one of the longest continuous run times - plus handy buttons to make choosing your settings that much easier.
Credit: Maggie Brandenburg

With an impressive longevity score, the Anjou 500ml ran for over 30 hours in our laboratory experiments. On top of that, it has our favorite timer settings of 1, 4, and 8 hours — enough to get most of us through a full night of sleep or complete workday (or nearly so). Another notable option is the Pure Daily Care, lasting over 20 straight hours, despite having a smaller tank of just 300ml. Similarly, the InnoGear 200ml Woodgrain holds only 200ml, yet lasted over 20 hours in our tests — longer than several 500ml diffusers.

The Pure Daily Care has a smaller capacity than many we tested...
The Pure Daily Care has a smaller capacity than many we tested (just 300 ml) but still managed to outlast several larger models.
Credit: Maggie Brandenburg

Ease of Cleaning


As much as we all wish we'd never have to clean anything again for the rest of our lives, that, unfortunately, is not the case. Especially for a machine that you're jamming oil into over and over again, the ability to clean it is essential. We tested each one's ease of cleaning by, well, cleaning them. We did our best to scrub every nook and cranny according to their directions. We also evaluated those directions (if they existed) against our expansive knowledge of diffuser care. And we assessed how easy or challenging each one is to take apart and put back together.

Don't Skip the Cleaning
Throughout even just a single use of your aromatherapy diffuser, the oil will start to build up on the inside of your device. This can not only change the aroma of subsequent essential oils you put in the unit but can also clog up the atomizer that makes it function. While every diffuser comes with different directions for cleaning, at the very least, you should expect to carefully rinse and wipe down the entire inside of your machine after every 2-3 uses or weekly. And always dry it completely before even short-term storage.

According to its instructions, and assuming you have white vinegar on hand, the Vitruvi is the easiest diffuser to clean. Its manual simply directs you to make a solution of water and vinegar and run it through the machine for 30 minutes. Even cleaning it with a cloth by hand is relatively simple — though the small neck at the top of the water chamber can be a little tricky without a cotton swab or tightly twisted paper towel. With some of the simplest insides to wipe down with a wet cloth, the RENWER and InnoGear 200ml Woodgrain are also easy to clean.

The Vitruvi is quite easy to clean by simply running it with a...
The Vitruvi is quite easy to clean by simply running it with a prescribed solution of white vinegar water.
Credit: Maggie Brandenburg

Featuring large, easily wiped down bases, the InnoGear 5-in-1 and AKASUKI are not far behind. However, they suffer from more complicated lids that have small spaces that are very difficult to cram a cloth into. A few of the models we tested have easy-to-clean bases but busy lids with many small crevices and slots that help create mist but are extremely difficult to clean. Those challenging models include the Homàsy and Anjou. However, cleaning the bases is far more important than cleaning the lids - though you should strive to cleanse both regularly.

The Anjou's base is simple to clean and the glass oil tube easily...
The Anjou's base is simple to clean and the glass oil tube easily slides out to be scrubbed separately.
Credit: Maggie Brandenburg

Features and Aesthetics


Assessing the aesthetic appeal of any product is a very subjective matter. However, we included some baseline characteristics to create an accurate assessment of both looks and exceptional features. We considered the number of colors and patterns each is offered in, particularly favoring woodgrains and other natural-looking exteriors. We compared how noisy they are relative to one another and other household noises, and paid attention to if those noises were the motor or the bubbling water. We took note of the lights — colors, brightness options, and available settings — and noted what additional materials they all come with.

The Art of Dilution
Every ultrasonic diffuser we tested comes with different recommendations for how many drops of essential oil to add to the unit. No matter which one you ultimately choose, start with the recommended dose and see if you like its strength. If you like subtle fragrances, just a few drops in 500ml of water may be enough. If you prefer stronger aromas or are covering the scent of something else (like a litter box or smoke), you may end up using half a teaspoon or more. Experiment with how much oil you use and be patient - you can always add more oil to your diffuser, but the only way to take some out is to dump it all and start again.

It's tough to find a room or space where the elegance and stylishness of the Raindrop 3.0 and ArOmis don't look great. Though different shapes, both these nebulizing diffusers feature simple wooden bases with clean lines and graceful glass tops in shapes that are both wonderful to look at and offer exciting views into the inner workings of the atomization process. While both these models are a bit lacking in features, they are some of our favorites to have decorate our homes. The Raindrop has one extra feature not found on any other model we tested — a magnetically attached power cord. Though it's not a flawless solution, this cord is much more likely to detach from the base when tripped over or yanked on, potentially saving the glass on top of the unit from crashing to the floor.

The Raindrop 3.0 features a magnetically attached power cord, which...
The Raindrop 3.0 features a magnetically attached power cord, which may help to stop the unit from falling over if the cord is accidentally yanked.
Credit: Maggie Brandenburg

The Vitruvi is the hands-down favorite ultrasonic model among our testers when it comes to sheer looks. This ceramic stone diffuser looks classy and classic. Available in four colors, it easily fits into just about any home decor. It's also exceptionally quiet, and though it has only a single light color and brightness, we find the peachy glow is pleasant and easy to appreciate. Also standing out in this category is the EQUSUPRO for its unique metal cover and exceptionally vivid lighting colors. We frequently found ourselves just watching them scroll through a full spectrum of vibrant hues for minutes at a time.

We had a hard time finding any spot in which the Vitruvi doesn't...
We had a hard time finding any spot in which the Vitruvi doesn't look good.
Credit: Maggie Brandenburg

Also scoring well are the ASAKUKI and RENWER, with extra features like WiFi compatibility (ASAKUKI) and a remote (RENWER). They both have woodgrain accents and pleasing shapes (the ASAKUKI's cube) or sizes (the RENWER's compactness) that make them a good fit in various rooms and workspaces. Notable as well is the Pure Daily Care, which is the only one we tested to come with essential oils — though those oils don't claim 100% purity, which we advise using.

Make your house smell like your home with the right diffuser.
Make your house smell like your home with the right diffuser.
Credit: Maggie Brandenburg

Conclusion


While each of the diffusers we tested are fully capable of spreading the scent of your favorite essential oil through the air, they are all different from one another and have unique qualities that make some better suited for large areas, some ideal for a work cubicle, and others a great nightlight or a thoughtful gift. No matter what aromatherapy diffuser you ultimately decide is the best choice for you, treating it kindly with 100% pure oils and regular cleaning will help it to be more effective and last longer.

Maggie Brandenburg