The Best Essential Oil Diffusers

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!

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 six months 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 noise. —Kat Merck

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.

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.