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• Best Ultrasonic Diffuser

  

  Photograph: Louryn Strampe

  Urpower

  Aroma Essential Oil (2nd Gen)

  Sometimes the simplest product is the best, and that’s the case here. The best-selling Urpower Aroma diffuser doesn’t have too many bells and whistles, but it works and it works well. There are two buttons on its housing: one to turn on the mist and set a timer (choose between 60, 180, or 360 minutes, or just leave it on), and the other to cycle among seven different colored lights (or turn them off entirely). You fill the little tank with water and add a few drops of your chosen scented oil. The tank holds enough water to run for about six or seven hours, and the diffuser will shut off automatically once the tank is empty.

  It puts out quite a bit of steam, which I personally found soothing during the dry winter while I was testing it. The scent strength and longevity depends on how many drops of oil you add to the tank. Note that the lid doesn’t lock onto the tank, so you’ll want to keep it in a stable place away from kids and pets (as you would with any other household tech).

  Type	Ultrasonic
  Additional Features	Light
  Oil Type	Bring your own
  Remote?	No

  WIRED

  • Optional light
  • Very simple to use

  TIRED

  • Lid doesn't lock

• Best Nebulizer

  I first learned about Pura from a friend whose house always smelled like a high-end boutique under every circumstance. Cooking project, water leak … no matter what was going on in her house at the time, I only ever smelled berries. I have two cats and a multi-sports-playing teen—I knew I needed this. Now, after having owned multiple Puras for over two years, I have some thoughts.

  While my Pura journey began with the now-discontinued Pura 3, I have also since tested the Pura 4 and large-room Pura Plus, both of which have dual bays for two of Pura's proprietary oil cartridges, as well as the Pura Mini. The Pura 4 and Mini both plug into an outlet and can only be controlled through the accompanying app (or Alexa or Google Home). This is convenient for setting schedules and timers, switching fragrances (or using the handy new auto-alternate feature), and changing the color of the optional night-light, but there have also been numerous occasions where I’ve wanted to stop or start or change a schedule but have been unable to because I forgot my password or the diffuser couldn’t connect to Wi-Fi. In the moment, it was infuriating. Mercifully, the stand-alone, cylindrical Pura Plus has on/off manual control buttons on the front. The smaller Pura 4 and Mini are best for enclosed spaces, like a long entryway for the former or a small bedroom for the latter (note that all Puras only work with 2.4-Ghz Wi-Fi). If you have high ceilings or any kind of open floor plan, you’ll get better results from the Pura Plus. Just note that, unlike the silent Pura 4 and Mini, the Plus emits an audible whooshing sound—32 decibels, about as loud as a fan on low.

  Perhaps the best feature of the Puras, however, is the brand's extensive library of scents from companies like Anthropologie, Nest, Capri Blue, and more. (Including luxe seasonal releases—spring offerings include Studio McGee Violet Fig, Brooklyn Candle Studio Tulum, and Otherland Chandelier, among many, many others.) The quality and duration can vary quite widely, and they're not cheap—$11 all the way up to $34, for 0.33 ounces—but most of them smell better than cartridges from any other diffuser brand I've tried, and all come with a 30-day money-back guarantee. Because of the small size and price of the cartridges, Pura might not be the best choice if you want to smell diffuser all day, every day, as you’ll end up spending a small fortune. However, if you love unique luxury scents and only need them occasionally and/or on demand, Pura is the way to go. —Kat Merck

  Type	Nebulizer
  Additional Features	Smart features (requires 2.4-GHz Wi-Fi), night-light
  Oil Type	Proprietary
  Remote?	No

  WIRED

  • Scents smell fantastic
  • App offers convenient controls

  TIRED

  • Can be loud
  • App and cartridges can be buggy

• Best for Pet Owners

  The Aera smart diffuser is gorgeous. I tested both the full-size version (a tabletop diffuser suitable for 500 to 1,000 square feet) and the Mini version (a plug-in diffuser suitable for 200 to 400 square feet). I like the modern design and that the Mini comes in an olive green or terracotta color option, though I wish the full size was available in fun colors too. I also like the way the little capsules stick out just slightly above the top of the diffuser. These are dead simple to set up, with or without the app. Plug ’em in, then select your proprietary fragrance capsule. The $60 fragrance-filled capsules come in different sizes for each diffuser, and the sizes vary by scent collection. Remove the capsule from its packaging, then remove the bottom plug followed by the top plug. Make sure to save the plugs for later use in case you want to swap scents midway through! Plop it in and your diffuser will get to work. There are manual controls for scent strength, starting a routine, and ejecting the scent capsule (on the full-size machine). The smartphone companion app lets you set a schedule, adjust fragrance strength, and reorder capsules (which are also available on Amazon). That’s the extent of the smart features you'll get here—unlike the Pura, Aera doesn't have Google Home or Alexa functions.

  Every scent I tried smelled good (my favorite was Sun's Out, which smells like sweet orange and lemon), and I like that the intermittent mist meant my room wasn't completely overwhelmed with fragrance. It was noticeable, but not aggressively so. If you want something that's going to coat your whole home in a scent, this isn't the best option. But for subtle freshness or to really amp up the smell of a small space, these are great. Especially Aera's True Loves line, which features Aera's proprietary OdorOut odor neutralizer and is designed for pet households.

  Editor Kat Merck tested these in both the regular Aera and the plug-in Aera Mini and found them significantly stronger than the classic Aera scents, and likely to cover most pet-related odors. The capsule longevity depends on how frequently you run it, and at what strength, but Aera says, “At a mid-strength setting (5 on Aera and 3 on Aera Mini) playing 10 hours a day, on average, capsules last approximately 60 days.” Best of all, these diffusers look good while they work—and they're reasonably quiet too (though louder than the Pura). Aera claims that its scents are hypoallergenic and safe for pets, though I still keep my cat away when using them. Just in case!

  Type	Nebulizer
  Additional Features	Companion app (requires 2.4-GHz Wi-Fi)
  Oil Type	Proprietary
  Remote?	No (though can be controlled remotely with an app)

  WIRED

  • Gorgeous design
  • Easy to set up and use
  • Optional app-based controls
  • True Loves scents with OdorOut are great for pet owners

  TIRED

  • Scents (though pleasant) can be faint

• Best for Small Spaces

  

  If you like to keep your bathroom or home office smelling fresh but find a smaller room overwhelmed by the scent put off by a full-sized scent diffuser, your answer may well be the plug-in Pura Mini smart diffuser. (Note that all Puras run on 2.4-GHz Wi-Fi only.) I’ve had it in my office for almost a year now, and so far it’s my favorite out of Pura’s lineup. Like its larger siblings, it has scheduling, scent strength, and automatic vial detection in the Pura app, and you can also change the color of the light and rotate the direction of the plug. It’s also a good option if you love the high-end, nontoxic Pura scents but want to buy them less often. I found one vial lasts well over a month on a 9-to-5 schedule, as opposed to a couple weeks in a regular-sized Pura. One downside: It will occasionally emit a very high-pitched, high-frequency noise when turning on. It’s not a consistent issue or especially noticeable when it is happening, but it is something to keep in mind if you’re super sensitive to sound. —Kat Merck

  Type	Nebulizer
  Additional Features	Smart features (requires 2.4-GHz Wi-Fi), night-light
  Oil Type	Proprietary
  Remote?	No

  WIRED

  • Companion app for scent control and scheduling
  • Light color and plug direction can be changed
  • Scents last a long time

  TIRED

  • Occasionally lets out a high-pitched electronic noise

• Best for Large Spaces

  Photograph: Louryn Strampe

  The Alo Yoga diffuser makes my house smell like an aromatherapy spa. It's sort of huge, measuring about 10 inches high by 8 inches across. But it looks nice enough when it's plugged in, thanks to its sleek, white, wellness-coded design (though the Alo branding is obvious unless you face the controls toward the wall, which I don't love). The water tank is massive, holding about a half gallon of water and requiring 25 to 30 drops of essential oil (which you supply). I tested this in conjunction with Alo's essential oils collection, which comes with six different oils (including three special essential oil blends). All of them smelled absolutely heavenly, and I liked the packaging and the leak-proof bottles, but you can also just supply your own oils.

  The diffuser itself is quiet and has onboard controls for continuous mist on high or low, a sleep mode (low mist without lights), timer buttons, and a light button. The light is soft and warm, with two brightness levels. The diffuser is pretty simple and straightforward to use, but the sheer size of it means that it can run for a long time and disperse a lot of scented cool-mist steam throughout your space. It could probably double as a humidifier, though I don't have the equipment on hand to measure the specifics. And I sort of love that it doesn't have an app or random remote controls. It's just a big ol' diffuser that does its job well. If you want a machine with a lot of throw or longevity that doesn't require its own proprietary oils, this is a very safe bet. Just be prepared to fork over some real estate from wherever you decide to place it.

  Type	Ultrasonic
  Additional Features	Light
  Oil Type	Bring your own
  Remote?	No

  WIRED

  • Pretty design
  • Scents easily fill large rooms

  TIRED

  • Large footprint

• Best Wireless Diffuser

  HoMedics

  SereneScent Waterless Rechargeable 120 ml Diffuser

  Standing 11 inches tall and looking like a skinny, cylindrical Bluetooth speaker, Homedics’ SereneScent diffuser first caught my eye at Costco, of all places. The “waterless” marketing on the box made me think you could use your own essential oils, but this is not the case. Still, the SereneScent diffuser is one of the only wireless diffusers I’ve seen (though you can use it with the cord), and I underestimated how much I would enjoy this feature. It’s not always convenient or preferable to put a diffuser near an available outlet, and the SereneScent lasts a surprisingly long time on one USB-C charge. (The manual says up to 14 hours, though I’ve been able to run it several hours longer. I do wish there were a battery indicator to show you how much power is left.)

  It also sports something else that’s rare among diffusers—full functionality without an app. There is one, of course, and it lets you set schedules and change the color of the light on the bottom, but otherwise the base features buttons for timers (one to eight hours), adjusting the scent strength (low, medium, or high) and light brightness, and turning the unit on and off. The stream of scent is visible out of a hole in the top, but it's intermittent. It's also nearly silent aside from a 34-decibel ssss00h0hhhh sound. The highest scent strength is also plenty strong enough to fill even large, high-ceilinged rooms. In fact, the only problem with this system at all is the price of the proprietary refills. They’re $60 apiece, many have inscrutable names like Parisian Affair and Enchantment, and there isn’t an obvious return policy. Granted, the scents I’ve tried (Apple Orchard, Frosted Cypress) are pleasant and high-quality, and the 4-ounce bottles really do last a month, but I just can’t ever see myself shelling out six Hamiltons for something I haven’t smelled in person. —Kat Merck

  Type	Nebulizer
  Additional Features	Customizable color light, timer
  Oil Type	Proprietary
  Remote?	No

  WIRED

  • No app necessary
  • Wireless and sleek
  • Pleasant scents

  TIRED

  • Proprietary scent refills are very expensive

• Best Portable Scent Diffuser

  Photograph: Louryn Strampe

  Zeya

  Portable Fragrance Diffuser

  This waterless diffuser from Zeya is unlike any other I've tried so far. It's a tiny rectangle that can be moved around the house (or car) or mounted somewhere using the adhesive-backed, removable back plate. It runs on three AA batteries. Instead of spraying scent into the air, the Zeya diffuses its proprietary scent cards with a small fan. Once switched on, the machine will diffuse the scent for two minutes, every 24 minutes, for eight hours. It then turns off for 16 hours. It's nearly silent, and you can choose between “high” or “low" scent strengths. That's it.

  When the scent runs out (which takes about 45 days on the low setting, though I started noticing a decline after 30), simply pop in a new scent card. The fragrances are complex, and I love how affordable and simple the whole package is. It's a very understated product. The scents are too faint to fill up a whole room, but I liked keeping this near my front entryway, near the couch in my living room, or in my bathroom. Just don't expect it to fill your whole home. Lots of customer reviews mention using this as a more powerful car air freshener, and I think it'd be great there too.

  Type	Fan
  Additional Features	N/A
  Oil Type	Proprietary scent cards
  Remote?	No

  WIRED

  • Easy to use
  • Can use anywhere, including the car

  TIRED

  • Scents can be faint

• Best Reed Diffuser

  

  The Drift reed diffuser is very aesthetically pleasing, with a minimalist design that should blend in no matter where you place it. It smells pretty strongly at first, and you can flip the singular reed as needed to strengthen the scent. The fragrance has better throw than the reed diffusers you might remember with the little sticks, and each refill lasts up to 60 days. I tested the Teak scent (which I liked), but there are three others.

  Reed diffusers are pretty passive, and depending on the airflow of a room, the scent stays pretty localized to the area where the diffuser is resting. The back of the toilet is a classic location, but you could also place it on the mantle, front entry table, or nightstand.

  Type	Reed
  Additional Features	N/A
  Oil Type	Proprietary
  Remote?	No

  WIRED

  • Pleasant scents
  • Easy to use

  TIRED

  • Not super strong

• Best for Multiple Fragrances

  

  The Atmos Tria diffuser is pretty chunky, but that makes sense considering it has room for three scents. You can swap among them easily using buttons on the diffuser or in the companion app, which is (thankfully) optional. The companion app lets you set up scent routines—maybe you swap from one fragrance to another at a certain time every day, for example—and remotely control the diffuser, as well as blend fragrances to create your own unique scent. The diffuser is also compatible with Google Home and Amazon Alexa for voice-powered scent routines.

  I like that the manual buttons allow you to skip the app. You can control the built-in light and the diffused scent very easily. I also enjoyed Atmos' scents, which are more perfume-like than air-freshener-like. Depending on how quickly you go through them, they might get pricey if you need frequent refills, since they're $25 apiece. But they all smelled fantastic, and it was fun playing with the different blending options. This diffuser is best for medium to large rooms.

  Type	Nebulizer
  Additional Features	App, Google Home and Alexa compatibility
  Oil Type	Proprietary
  Remote?	No (though can be controlled remotely with an app)

  WIRED

  • Sleek
  • Holds multiple fragrances
  • Unique scent options thanks to blending capability

  TIRED

  • Scents can get pricey depending on how you use them

• Best Scent Diffuser Subscription

  

  I'm a fan of Drift's vehicle air fresheners, and this little plug-in diffuser is great for at-home use. It has a small form factor and is best used in areas like the bathroom or home office since it isn't powerful enough to scent a large room (though it handled a medium room just fine). There are three scent strengths, and the refills last about 30 days on the lowest setting. The plug can be rotated to fit different outlets, and I like the magnetic cover that snaps back into place after refilling the scent. The 22-ml scent refills come in all sorts of fragrances, including some limited-edition monthly scents. This is sold as a starter pack with a subscription to get you new scent refills every month, but you can pause or cancel your subscription easily at any time. (My favorite scent is Coconut Pistachio.)

  The only gripe I have with this diffuser is that the scent cartridge refills can be leaky if they aren't stored upright, so just keep that in mind. It's not a deal-breaker for me.

  Type	Nebulizer
  Additional Features	Subscription model available
  Oil Type	Proprietary
  Remote?	No

  WIRED

  • Compact
  • Easy to use
  • Fantastic scents

  TIRED

  • Scent refills can be leaky

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