What's The Difference Between Active Diffusers and Passive Diffusers?

by Annie Mascia March 02, 2023

AAA: What's The Difference Between Active Diffusers and Passive Diffusers?

Embracing aromas to offset bad odors was a common practice centuries ago in Egypt and Asia as well as in Greece and ancient Rome. The process of dispersing aromas at that time primarily took the form of passive diffusion. The utilization of aromatic oils in Egypt is widely known and were used for religious rituals, embalming, as gifts for the afterlife, to mask the odor from sacrifices and to honor their Gods. Pythagoras evidently transported the use of reed diffusers from Egypt to his home in Greece and in Rome, diffusers were often used in temples to clear the air of malodor. 

That being said, aromatic and passive diffusion has been around for centuries and the only thing that has really changed is that today, diffusers have evolved to fit into our modern lifestyle. We are lucky in this contemporary time to have a plethora of diffuser choices. Although, this choice in itself can be just the problem - with so many to choose from, how do we know which one is right for us and our lifestyle? Oh, and by the way, no one ever said you need only one.

Read on for a detailed description of Active vs Passive diffusers so that you can wrap your head around and sort out the differences to discern which ones are best suited for your needs - whether in your home or workspace - or even your car!

Active vs Passive Diffusers

As you may have sussed out already, diffusers are broken down into two main types: Passive Diffusers and Active Diffusers. 

Passive essential oil diffusers are simple and perhaps somewhat underestimated. The diversity of these gems comes in many different forms and perhaps one of the best things about them is that they do not need a stimulus such as electricity or vibration to emit the essential oil molecules into the air. Another major difference is that since they don't have a catalyst, the molecules dispersed in the air are more subtle and slower moving. They work best for those who do not want an aroma to be overpowering. 

Passive Diffusers 

Reed Diffuser 

The Reed Diffuser is a really, really clever and elegant instrument for passive diffusion. Its simple construction entails 8 - 5” petite wooden reeds, a wooden cap that replaces the plastic cap on an essential oil bottle and a wooden tray to sit the bottle on. It fits best on an Edens Garden 10ml bottle - single or blend. 

It's a perfect device for small spaces and powerful enough to delicately invigorate any room. Here’s how it works: when the reeds are placed into an essential oil bottle, over a few hours, the wooden reed soaks up the essential oil. As the absorption process is happening, the reeds give off a steady but subtle aroma of the oil into the air. 

To refresh the bouquet from the bottle and reeds, simply flip the reed sticks every 1-2 days until all of the oil has evaporated. The reed diffusers last 1-2 weeks in total. Edens Garden Reed Diffusers and your favorite essential oil single or blend make a perfect gift for a housewarming party or birthday as well as just for friendship!

Ceramic Bloom Diffuser 

The Ceramic Bloom Diffuser is as petite as a small flower pot. This innovative, passive diffuser works in a similar way to the Reed Diffuser by subtly and gently releasing aromatics into the air that it has absorbed through a cotton wick. Its simplicity and aesthetics would fit snugly into any home or office.

The “flower pot” has three parts that fit together easily. The base is charcoal colored and unglazed on the outside. Its inner enclosure is glazed to contain and hold the essential oils you add to it. A wooden disk with a centered hole fits on top of the base and the porcelain clay bloom perches atop the wood. The white porcelain clay bloom itself has a 5-inch cotton rope attached to its underside that slips into the base via the hole in its wooden seat. To enhance the aroma, add a few drops to the bloom. It can hold 5-30 ml of essential oil in the base.

To use it, pour the desired essential oil single or blend into the base, thread the rope of the porcelain ceramic bloom through the hole of the wooden disk and sit the disk and bloom on top of the base where the rope mingles with and absorbs the essential oil. In over an hour or so, the rope will absorb the oil, carrying its aromas to the unglazed porcelain ceramic bloom where it emits the essential oil molecules for your gratification and pleasure.  

Aromaride Car Diffuser 

Small enough to fit into the palm of your hand, this passive diffuser needs an active stimulus to emit essential oils into the air. The Aromaride Car Diffuser, therefore, falls into a bit of a grey area in the active vs passive diffuser war. 

At just 3 ¼ inches wide, its clip-on design effortlessly fits into the slats of your car's fan vent. When your car fan is running, the airflow stimulus allows the evaporation of essential oil molecules into the air. This mini-diffuser comes with four replaceable wicks and extra wicks are conveniently available on Edens Garden website. 

To use this prized possession, ready the Aromaride Car diffuser by unscrewing the two metal pieces. Place one removable wick in a small bowl or plate and add 5-15 drops of your favorite EG single essential oil or synergy blend. Using a tweezer, tuck the wick into the inner metal portion of the diffuser and push it in to secure it. Screw the diffuser back together, turning the dial so the small white arrow matches with the dots. Clip it onto the car vent and enjoy your drive! 

Add more drops every week or so of the same essential oil single or blend. After a few uses or in want of using a different essential oil or blend, the wick should be replaced.

Jewelry Diffusers

An inventive idea to be both fashionable and functional, wearable jewelry diffusers are not to be overlooked. This colorful collection contains Lava beads which can be found on each of Edens Gardens' bracelets. Lava beads are porous and able to hold onto the aroma of essential oils to give your their therapeutic benefits on-demand as passive diffusers. 

To use the jewelry diffusers, apply 1-2 drops of your favorite oil or blend to the lava stones. When looking to swap out with a different oil, you can clean the beads by soaking them in a 1:1 solution of water and grain alcohol for approximately 3 hours and letting them air dry. Some of the aromatics of the previous oil may still be detectable.

Our bracelets are as follows, one of which is long enough to double as a necklace: 

  • Capri wrap is 20” in length and can double as a wrap bracelet or as a necklace. It contains a mingling of 4 mm stones: Lava, Moonstone, Howlite, Jade, Mother of Pearl, Rhodonite, Topaz, Aventurine, Spotted Jasper and Frosted Clear and Rose Quartz. 
  • Catalina Bracelet is 7” in length and made with 8mm stones of Tibetan Agate, Aquamarine and Lava.
  • Cayman Bracelet features 7” of brilliant contrast with 8mm stones of Howlite, Tibetan Agate and Lava stones.

Active Diffusers

Active Diffusers need a stimulus to emit essential oils into the air. Those triggers can fall into any of these categories: nebulizing, ultrasonic and evaporative. Active diffusion allows the molecules of the essential oils to be scattered into the air in a more heightened, powerful and vivid manner due to the faster dispersal of the essential oils. 

Ultrasonic Diffusers are the most popular Active Diffusers. They are nearly silent in operation and work due to a small plate at the base of the device that vibrates rapidly (ultrasonic vibration), moving the water and oils that create its fine mist. 

General operating instructions for Ultrasonic diffusers are somewhat universal:  

  • Remove the outer cover and water tank lid
  • Add room temperature water to just below the fill line of the inner container (according to the product's instructions). If you receive a measuring cup with the diffuser, use it to ensure adding the proper quantity of water.
  • Add 6-10 drops of essential oil per 100 ml of water and cover the inner container with its lid. 
  • Place the outer lid on the diffuser.
  • Plug in the power adaptor to an electric outlet.
  • Turn it on by pressing the mist button once.
  • If the device has special instructions for intermittent use, refer to the product instruction sheet.

Terrazzo Ultrasonic Diffuser 

The Terrazzo Ultrasonic active diffuser is in a category all of its own. Its outer beauty is stylish and unique and would fuse well in a variety of decor settings holding some prominence in any location at nearly 5” x 6.5” in size. The outer shell is artisan made and crafted of stone assuring that no two pieces are alike. It features a large tank with 130 ml water capacity and is ideal for large spaces and does not have to be refilled often.

It has multiple mist settings giving flexibility to its functional design. When the mist button is pressed once as a general setting, the diffuser will turn on and automatically shut off after 3 hours. When you press the mist button more than once, you will arrive at intermittent settings. For example, pressing the button twice will allow the machine to work for 30-second intervals and shut off after 8 hours. This setting would be ideal for nighttime use to help usher in restful sleep with any of our sleep blends. It is recommended that the Terrazzo be placed in a stable and level location when using and to add 13-18 drops of essential oil single or blend. 

For more information on use and safety, please refer to Terrazzo’s instruction booklet or the Edens Garden website page

Diamond Ceramic Diffuser 

The Diamond Ceramic essential oil diffuser also falls into the ultrasonic category of Active Diffusers. Slightly more compact with a 90 ml water capacity, this diffuser will not disappoint.  It allows you to customize the delivery of essential oils with its interval and intensity settings, exactly like the Terrazzo. If it weren’t for the delightfully intense aromatics this diffuser emits, you would forget it was in the room due to its quiet operation.

It stands approximately 7.2” tall and 4” wide and comes with a choice of three colors, white, black and tan allowing it to style itself easily into any home or office space. 

For more information on use and safety, please refer to the Diamonds instruction booklet or the Edens Garden website page

Portable Mio Mist Diffuser

Employing rechargeable battery-operated mechanics, this compact active diffuser can cover a four-square-foot space and it functions via a micro ultrasonic plate. Its modest size makes it perfect to carry for on-the-go use. Heading out of town? Pack this little gem up with your favorite oils and rest assured all your creature comforts will be there for you when needed. 

Sizing up at just under 4” in height and 1” in width, the Mio Mist portable diffuser is perfect to use when in a small personal space and advantageous during travel. We consider the Mio Mist as a must-have diffuser in one's aromatherapy arsenal. It functionality proves its worth with its water level sensor and light signals - a white light when in use and a red light when charging. The product comes with a USB charger and will last a 15 hours on a full charge. Thats a lot of punch for such a mini machine. When in use, it turns on intermittently for 60 seconds. Cleaning is recommended with lukewarm water when not in use or when swapping essential oil singles or blends. 

Portable Personal Diffuser 

This essential oil inhaler functions by using one's own inhalation and is effectively active in function but also falls into the gray area of diffusion due to it having a lack of stimulation on its own. This sleek and compact device is 3.5" tall and .75" in diameter and is perfect for on-the-go use. It's great for adults and kids alike - indicated for use in spaces where room diffusion is not possible such as in a classroom to alleviate anxiety before a test or while traveling to defend yourself against germs or to loosen up stuffy sinuses. 

The interior of the inhaler includes a cotton wick and a glass container. To fill this pocket diffuser, separate the cap and remove the inner glass container. Unscrew the silver cap on the glass container and add 5-15 drops of essential oil to the cotton wick. Replace the wick into the glass container and screw the metal cap back onto the glass container, placing it back inside the outer tube.

To benefit from the inhalation of the oils on the wick, uncap the outer tube and hold the open end up to your nose and breathe deeply into each nostril 4-5 times, closing the opposite nostril with your finger if necessary. Use as often as needed.

Depending on how often you use your personal inhaler, the aroma can last up to two months. When in need of a replacement wick, we recommend using cotton balls to replace the wick. If changing essential oils or essential oil blends for use in the portable personal diffuser, clean out the glass insert with soap and water and/or alcohol first to avoid mixing aromatics. 


When diffusing essential oils in a space with numerous people, it is recommended to ensure that everyone near does not have health conditions such as allergies or sensitivity to the essential oils being used. Some essential oils can bring on negative reactions especially in regard to young children and asthmatics and those on medications.  

  • With children under the age of 10 and asthmatics some essential oils can restrict breathing due to the component 1,8 cineole. 
  • If pregnant or nursing it would be wise to avoid the use of essential oils.
  • Some essential oils can interact adversely with those on medications. 
  • For school situations, it's best to use a personal inhaler. 
  • Pets should be given the freedom to leave a room if they are present when a diffuser is in use. 


  1. Ancient Egyptian Perfumes https://www.styleforwanderlust.com/the-style-for-wanderlust-blog/2018/11/28/ancient-egyptian-perfumes-on-the-trails-of-the-lost-fragrances-of-the-pharaohs-queens#:~:text=Specifically%2C%20perfume%20was%20very%20popular,to%20communicate%20with%20the%20gods.
  2. How Do Oil Diffusers Work? https://www.lifestylepackaging.com/useful-resources/diffuser-packaging/how-do-essential-oil-diffusers-work/#:~:text=An%20electric%2C%20ultrasonic%2C%20diffuser%20dispenses,which%20disperse%20into%20the%20air.
  3. The Guide to Using an Aromatherapy Diffuser in Massage https://www.massagemag.com/the-guide-to-using-an-aromatherapy-diffuser-in-massage-132738/
  4. Types and Differences of Essential Oil Diffusers https://scentfill.com/blogs/air-freshener-plug-in-refill-blog/types-and-differences-of-essential-oil-diffusers-and-scented-oil-plug-in-warmers
  5. Guide to Essential Oil Diffusers https://www.aromaweb.com/articles/diffu.asp

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