Sort of like cars and boyfriends, essential oil diffusers come in a variety of makes and models. If you're a fragrance connoisseur like we are, there are four types you should be familiar with: evaporative diffusers, heat diffusers, ultrasonic diffusers, and cold-air diffusers (also known as nebulizing diffusers).
Cold-Air (Nebulizing) Diffusers
Cold-air diffusers, also called nebulizing diffusers, use pressurized air to break essential oils into micro-particles. The particles are distributed by a pump, similar to a perfume atomizer (but far more effective).
There’s no heat or water required for this method, so the oil stays in its purest form. Cold air diffusion can be more expensive than some of the other options, but you truly get what you pay for in terms of fragrance longevity and purity.
Evaporative Diffusers
Evaporative diffusers use air movement to distribute essential oils. The oil is added to a filter or a piece of fabric, which gets inserted into the machine. A built-in fan blows air through the filter, causing the oil to evaporate and move throughout the room.
Evaporative diffusion is fast and the diffusers are extremely affordable, but it should be noted that they require substantially more oil than other methods because a portion is absorbed by the filter. Quality essential oils can be pricey due to the therapeutic benefits and the production process, so the thought of wasting them makes us cry a little inside. Evaporation also interferes with the oil’s scent profile, which can hamper its restorative effects and alter the scent profile slightly. More on that later.
Heat Diffusers
Heat diffusers use a heat source to warm the oil until it evaporates. Sometimes the heat source is a flame placed directly under a tray of oil. In other cases, the oil is mixed with water and distributed into the air as steam.
If you’re on a tight budget, heat diffusers are usually affordable. Unfortunately, heat changes the molecular structure of essential oils, so any therapeutic benefits you’re expecting might be changed or lost completely. That calming bedtime blend could suddenly have you feeling energized and ready for a workout.
Ultrasonic Diffusers
Ultrasonic diffusion uses ultrasonic vibrations to create a fine mist of water and oil that floats around the room. These devices only require a few small drops of oil, and there is no heat involved, so the oil’s molecular structure is unaffected.
Water is added to the oil and the air, so ultrasonic diffusers act as humidifiers. This could be a pro or a con, depending on where you live and if you enjoy humidity.
With this type of diffusion, the oil is very diluted, so expect a subtle scent. Ultrasonic diffusers work best where there is natural air movement to spread the mist. They do not typically have a mechanism to spread the scent far and wide.
Why We Love Cold-Air Scent Diffusion
Ultrasonic diffusers are often marketed as state-of-the-art, but cold-air diffusion is the gold standard when it comes to using therapeutic, high quality essential oils and fragrances.
We already mentioned that ultrasonic diffusion dilutes oils with water, lessening their healing effects and creating a humid environment. With cold diffusion, oils stay in their original, concentrated form. The oil molecules are nebulized, meaning they are split into thousands of safe, tiny particles.
This process works the same way as an inhaler and is ideal for delivering medicine to the body. Using cold-air diffusion is by far the most effective way to enjoy the benefits of essential oils. The scent distribution is consistent and customizable, and the fragrance intensity is just right.
Cold air diffusion is also efficient. You only need to use a few drops of essential oil to scent an entire room. No residue remains in the diffuser after each use, so you can switch scents without worrying about unwanted mixing. There are zero messy cleanups.