How Essential Oil Diffusers Work and their Benefits

Essential oils like lavender, peppermint, bergamot, eucalyptus and rosemary have been used for ages for their calming effect, relieving stress, improving sleep and cognitive functions among other benefits.

The only thing that has changed over time is how essential oils are released in the air. You see, essential oils have a delicate chemical structure which should not be altered by heat or other processes. They also need to be evenly dispersed in the room. And that is where essential oil diffusers come in.

essential oil diffuser

Oil diffusers are gadgets which transform essential oils into a mist of microscopic droplets and releases them in the air, allowing you to experience the aroma of the oils for extended periods of time.

Oil diffusers break down essential oils into tiny droplets without altering their chemical formula before releasing then in the air in the form of a mist. The essential oils help in calming nerves, improving sleep, pain relief, nasal decongestion, appetite control, stress relief etc.

Oil diffusers also help in releasing the right concentrations of essential oils in the room. They ensure that the essentials oils released in the room are neither too concentrated nor too weak/insufficient.

Essential oils diffusers use 4 ways to diffuse oil unto the air. The 4 ways are:

  • Evaporation
  • Heat dissemination
  • Nebulization
  • Ultrasonic vibrations

When buying an oil diffuser, it is important to first find out which method they use to transform the oils into the mist/fog. It also helps to understand the difference between the 4 types of diffusers.

Note: If you have a humidifier, you may be tempted to use it as an oil diffuser. Although they look similar and even work almost the same way, humidifiers should not be used with essential oils and other inhalants.

I will tell you the difference between oil diffusers and humidifiers at the tail end of this blog. For now just know that you shouldn’t add essential oils in a humidifier.

Types of Oil Diffusers

Oil diffusers work differently but the goal is the same; break down essential oils into tiny droplets without altering the chemical structure then release the droplets in the form of a fog, spreading then evenly across the room.

Breaking down essential oils from a liquid to tiny particles is vital since the tiny particles are light enough allowing them to be suspended in air and move about easily.

The following are the different types of oil diffusers based on how they work:

1. Evaporative Oil Diffusers.

evaporative essential oil diffuser

What happens when you leave a bowl of water outside the house for a few hours during the day? The level of water in the bowl will reduce since some of the water will evaporate into the air. That is how evaporative oil diffusers work.

Evaporative oil diffusers work through evaporation. When the essential oils turn phase from liquid to gas, the aroma spreads across the room and that is how they get to your nostrils.

It is important that I mention that evaporative oil diffusers do not use a heat source to break down the essential oils into steam. Instead, they use the heat already in the room to evaporate the oils.

Because the rate of evaporation depends on the heat in the room, evaporative essential oils can be a little harder to control. Sometimes the aroma can be less and at other times it can be more intense.

Modern evaporative oil diffusers use a fan to vaporize the essential oils. The fan pushes a breeze of air through the essential oils causing them to evaporate. These diffusers gives you more and precise control of the diffuser since you only need to turn the fan on and off.

2. Heat Oil Diffusers

Heat oil diffusers work just like evaporative diffusers but with a source of heat. These diffusers need a heat source to boil the essential oils until they vaporize. The steam is then released in the air.

Heat diffusers break down essential oils into a mist of microscopic droplets through heat application. There are more than one way of applying heat to the essential oils.

Some heat diffusers use a flame from a candle to heat the oils and when they achieve their boiling point they will evaporate and release their scent in the air. There are also those which use an electric heating coil.

Electric heat oil diffusers are operated by a thermostat which prevents overheating of the essential oils which could damage the quality of their scents.

Heat oil diffusers are inexpensive and are great for folks who want a quick aromatic therapy. Their main disadvantage is that heat application has the potential to alter the chemical composition of some oils, making them less or even more intense depending on their properties.

Also, heat oil diffusers with an open flame can pose a danger if you have kids or pets in the house due to the risk of burns.

3. Nebulizing Oil Diffusers

Nebulizing diffusers work just like hospital nebulizers. Nebulizers are used in hospitals to administer medicine in the form of a mist. The simply turn liquid medicine into a mist which can then be easily inhaled.

Nebulizer oil diffusers turn essential oils into microscopic droplets by combining them with pressurized air. Just think about how aerosols work.

Air pressure is applied inside the can which then breaks down the aerosols into tiny droplets which are released from the can in the form of a fog/mist. It is the same principle that is used in nebulizer diffusers.

Nebulizer diffusers releases essential oils in their purest forms. These diffusers do not require heat or water to be added into them. They therefore release a concentrated stream of essential oils whose chemical structure has not been interfered with.

For people with breathing difficulties like asthma, nebulizer oil diffusers offer quicker and long-term relief than even inhalers since they allow more medication to flow to the lungs over a long period of time.

Apart from being low-maintenance, nebulizing diffusers are plastic-free which also means they are great for the environment.

4. Ultrasonic Oil Diffusers

ultrasonic essential oil diffuser

Ultrasonic oil diffusers work exactly like ultrasonic humidifiers and that is exactly why they are also known as humidifying oil diffusers. They use electronic vibrations to break down essential oils into tiny droplets which are then released in the air.

Ultrasonic oil diffusers work by using a plate which vibrates at an ultrasonic frequency. The vibrations transform the oil into microscopic particles which then disperse in the air.

These diffusers have a water tank which is filled with water and then a few essential oils drops are added. The vibrations causes the essential oils to mix with water and the released in the air in the form if a cool mist.

Despite the vibrations created by these diffusers, ultrasonic diffusers are not noisy. They are therefore a great choice for use in offices or other areas where noise is unwanted.

Ultrasonic oil diffusers do not use heat. As I said, they work more or less the same as ultrasonic humidifiers which fall under cool-mist humidifiers (and not warm-mist humidifiers which uses heat).

Another advantage of ultrasonic oil diffuser is their humidifying effect. Since these units use water, they can also be used to humidify the air as well especially during winter when the air tends to be dry and asthma conditions tend to worsen.

The Benefits of Using Essential Oil Diffusers

lavender essential oils

The benefits of using an essential oils from a diffuser are:

  • They have a calming effect
  • For stress relief
  • To treat colds and other respiratory conditions
  • Help with digestion
  • Energy-boosting
  • Improve sleep
  • Appetite control
  • Mosquito repellant
  • Pain relief
  • Improve cognitive functions

Let us look at them in more details.

1. Stress Relief/Calming Anxiety

Essential oils have been found to provide a calming effect, by lowering down the blood pressure thereby providing stress relief. If you need to calm down or help dealing with anxiety, lavender is especially a good essential oil for that.

2. Decongestion/Breathing Better

If you are suffering from colds, nasal congestion or other forms of respiratory problems, eucalyptus essential oil can help you breath better. Eucalyptus oils are effective in clearing the nasal air passage and can also help you with your sleep.

3. Help with Digestion

If you would like help with digestion or muscle aches, basil would be a good essential oil to consider. Basil helps in restoring the natural pH of the body and also feeds the good bacteria in the stomach which is why basil is even more effective when ingested.

4. Boost Energy Levels

Essential oil diffusers can be used to boost energy levels. Bergamot or cardamom or a blend of the 2 oils can help to lift your spirits and/or help you to mentally focus on a task or/and gain clarity.

5. Sleep improvement

Do you have problems falling asleep? Diffusing essential oils can help you fall asleep quicker and sleep well/for a long time. Some of the best essentials oils to help with sleep are lavender, rose, Roman chamomile and jasmine.

For more information on how essential oils can help you sleep better among other things, check out this post by the Sleep Foundation.

6. Bacteria and Mold Control

Some essential oils make the air inhabitable for bacteria and mold. They make the air unconducive for the growth of harmful bacteria and mold. Eucalyptus, tea tree and thyme are especially good for that.

To deal specifically with mold you can use pine and thyme essential oils

7. Pain Relief

Muscle pains, sore joints, headaches and other pains can be dealt with using essential oils. While application of the oils is more effective, diffusing the oils works just fine. Peppermint, wintergreen, eucalyptus, ginger, lemongrass and Roman/German chamomile can help to deal with body pains.

Oil Diffusers vs Humidifiers


 Although they look similar and even work almost the same way, humidifiers and oil diffusers are designed to do different things. As we have seen, the function of an oil diffuser is to break down essential oils into fine particles which are then released in the air.

Humidifiers are used to release moisture in the air, thereby increasing the relative humidity of the house. There are small room humidifiers for humidifying a single room and then there are central/whole-house humidifiers.

At certain times of the year, especially winter, the air contains almost no moisture (mainly in arid states). The dry air causes negative effects on health and the house like:

  • Dry and itchy skin
  • Respiratory infections
  • Dry irritated eyes
  • Nasal congestion
  • Nose bleeding
  • Static electricity
  • Cracking of wood products

Humidifiers are therefore used to increase the moisture content in the air thereby preventing the above problems. Just like diffusers, humidifiers transform water from a liquid into a warm or cool mist/fog which can then dispersed in the air.

The ideal indoor humidity is between 30% and 50%. A humidistat ensures that the humidity in the house is maintained with that range.

The following are the different types of humidifiers:

  • Heat humidifiers
  • Evaporative humidifiers
  • Ultrasonic humidifiers
  • Impeller humidifiers

Humidifiers are categorized as warm-mist or cool-mist humidifiers. Warm-mist humidifiers use heat to evaporate water while cool-mist do not need heat and include evaporative, ultrasonic and impeller humidifiers.

There are lots of people who add essential oils and other inhalants in humidifiers in an attempt to kill 2 birds with one stone. Should you do that though?

Humidifier manufacturers do not recommend adding essential oils in humidifiers. The essential oils can damage the humidifiers and the warranty will definitely be voided.

Wrap Up

And basically that is how essential oil diffusers work and their benefit. I hope that this guide was helpful.