Which Diffuser Is the Best? Diffusion Methods and Comparison Charts

We are often asked by our customers which diffuser is the best. However, with so many different diffusers available (each with its own benefits and limitations), we’ve found that the only way we can answer that question is like this: It depends on what you like in a diffuser.

There are 4 different categories of diffusers available on the market today. Each of these differs in the way that it puts essential oils into the air, and each has different benefits. These 4 categories include the following: nebulizing diffusers, ultrasonic or humidifying diffusers, evaporative diffusers, and heat diffusers.

Nebulizing Diffusers

A nebulizer works basically the same way a perfume atomizer works. A jet of air blowing across a small tube creates a vacuum that pulls a liquid at the bottom of the tube to the top of the tube. The airflow blowing across the surface of the oil at the top of the tube blows the oil away in a fine spray or mist. With a constant air supply source, this type of diffusion can quickly put a large amount of oil into the air.

Because this type of diffusion works to put the whole oil into the air in the form of tiny droplets, it is often considered the best type of diffusion for the therapeutic use of essential oils.

Since nebulizing diffusers work so powerfully to quickly saturate the air with essential oils, they generally run at a higher sound level, and they tend to use oil at a higher rate than any other type of diffuser. We generally recommend using a timer with any nebulizing diffuser and setting the timer so that the diffuser is only on for the shortest amount of time possible and off for the longest amount of time possible. This not only helps to conserve oils, but it also allows the olfactory system time to process the oils and recover before receiving more. Our most popular model of a nebulizing diffuser (the Advanced Essential Oil Diffuser) features built-in settings that allow you to control both the airflow and the amount of time the diffuser is left on and off. This enables you to control how much oil is being diffused at a time. For those who want to be able to quickly saturate the air in a room with the whole oil, this system just can’t be beat!

Ultrasonic or Humidifying Diffusers

Like nebulizing diffusers, ultrasonic diffusers also create a fine mist, but the method by which this is accomplished is very different. An ultrasonic diffuser uses electronic frequencies to cause a small disc under the surface of a liquid (usually water) to vibrate at a very fast rate. These ultrasonic vibrations break the essential oil into tiny microparticles, dispersing the oil in a fine mist. These tiny particles are more easily absorbed by the lungs for a greater therapeutic effect on the body, mind, and spirit.

While the transformation of water or other liquids into vapor normally requires great heat, the transformation of these liquids into vapor is accomplished through an adiabatic process, which means the change in state of the liquids is accomplished without any kind of heat at all.

While this type of diffusion creates a lovely mist that helps to humidify the air and features the gentle sound of trickling water, only a small fraction of the mist is actually essential oil, and it depends solely on the air current already in the room to disperse the mist throughout the room. For those who desire only a small amount of oil to be diffused in a room, this type of diffuser not only works well but can also be very beautiful.

Our most popular humidifying diffuser is the Whisper Diffuser because the oil never touches the moving parts, it is easy to clean, and it has timer settings that allow the diffuser to run off and on for up to 9 hours. This diffuser is great to use at night because it can run all night and is quiet enough to allow a good night’s rest.

The USB Diffuser and the Ultra Mini USB Diffuser are both very small and can be used anywhere that has a USB connection or adapter. The Ultra Mini USB Diffuser makes a great starter diffuser because it is inexpensive and works well. It is also a good choice for use around children because the water won’t leak if the diffuser is tipped over.

Because ultrasonic/humidifying diffusion is the most popular diffusion method, there are many different ultrasonic diffusers to choose from. In fact, we have recently added several ultrasonic/humidifying diffusers to our product line. See the full selection at AromaTools by clicking here: Ultrasonic Diffusers.

Evaporative Diffusers

Evaporative diffusers are pretty basic in how they operate. A fan blows air from the room through some sort of pad or filter that has essential oils dropped onto it. The air blowing through the pad causes the oils to evaporate more quickly than normal, and the air with the evaporated oil is blown into the room. The Whispi Diffuser is a little unique because the pumping action with your finger pushes the air through the scent cell and picks up the aroma of the essential oil and blows it out for you to smell. One of our newest diffusers, the Fidget Fuser, diffuses as you spin it and is one of the most popular options for children or teens (especially boys).

Another type of evaporative diffuser doesn’t require a fan to blow the oil around, but uses the air current existing in the room to subtly diffuse around a small area. These diffusers are usually personal diffusers such as necklace pendants, bracelets, personal oil inhalers, or pens. Some can even be absorbent beads placed in a mesh bag to diffuse in a small space.

While this method of diffusion works well at getting the scent of the oil into the room or around your personal space, there is one drawback to this method: anytime an essential oil evaporates, some of the lighter, or more volatile, components of the oil tend to evaporate much faster than the heavier and less volatile components. This means that instead of getting the whole oil all at once, you are getting a higher percentage of the lighter components at the beginning of the process and a higher percentage of the heavier components towards the end of the process.

While this fractioning of the oil may diminish any therapeutic properties that the whole oil possesses, evaporative fan diffusion is still a good and relatively quiet means of getting the aroma of the essential oil throughout the room, and evaporative personal diffusers are great at containing the aroma within your personal space.

These types of diffusers work well in a car where the air conditioning blows the oil around. Click here for more information about diffusing in the car.

Heat Diffusers

Like evaporative diffusers, heat diffusers also cause the essential oils to evaporate quicker than normal but use heat instead of blowing air to accomplish diffusion.

While some heat diffusers use high levels of heat to produce stronger smells, the best heat diffusers will use only very low levels of heat to produce subtler aromas. This difference is important, because high levels of heat can actually alter the chemical constituents of the oils.

Although heat diffusers do share the same drawback of any diffuser that relies on evaporation—the potential of breaking up the oil into its components instead of putting the whole oil into the air––heat diffusers are a very economical and totally silent method of diffusing.

Diffuser Comparison Charts

Click on a chart to enlarge.

15 thoughts on “Which Diffuser Is the Best? Diffusion Methods and Comparison Charts

  1. Pingback: “Heavenly Air” Diffuser Blend | AromaTools Blog

  2. My grandson has cystic fibrosis and his mother was saying that his respiratory Dr. Didnt recommend diffusers because of something like the water molecules can carry something that wouldn’t bother normal people but are bad for him.
    Would a heat/fan type be best?

    • Michelle, you could try an evaporative or heat diffuser. A nebulizing diffuser doesn’t use water, but if used a lot (for more than 15 minutes without a break) it could irritate the olfactory system on normal people, so I’m not sure how it would affect him. Nebulizing diffusers tend to be more expensive anyway, so I recommend starting with an evaporative or heat diffuser first.

  3. lots of information- very useful, but layout is a mess… ‘some assembly required’. you badly need a summary paragraph, with a few recommendations for different types of users.
    i for instance am a noob- just want a recommendation of one or two diffusers that are safe and cheap to try.

    • The best diffuser to use for a therapeutic benefit is the Advanced Essential Oil Diffuser and the second best is the Whisper Premium Silent Misting Diffuser because it can run (off and on) silently all night long.

  4. When I turn on the diffuser with two drops of lavendar on the pad it seems I get a headache (I am sitting right next to the diffuser. Could that be the cause of my headache that I am to close to it.

    • It is unlikely that your headache was caused by sitting too close to the diffuser. There are many reasons you could be experiencing a headache when diffusing such as the following: you may be using a low quality essential oil, you may have a negative association with the scent, your body may be reacting to the oil and possibly beginning to detoxify, or your headache could be due to an unrelated cause such as stress, tension, or dehydration.


  6. I wanted to let you know how much we have enjoyed the Whisper diffuser!!! We have two for about 3 years and have had no problems whatsoever!! They are very easy to clean! One cup last us about 2-3 months. We only put about 5 drops of oil in and it can run up to 8 hours. We constantly have it running! You can have the light on or off. It’s Wonderful!!!

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