Aloha Bay tested and evaluated dozens of aromatherapy diffusers before deciding to design and create the most effective and least expensive diffusers on the market. Further below is a description of the different types of aromatherapy diffusers we reviewed.
Heated Aromatherapy Diffusers
Heating an essential oil is necessary especially for the heavier, more resinous oils, such as frankincense, and myrrh, but it also works great for the citrus and grassy oils. A small minority of aromatherapy purists argue that heated essential oils don't have the same healing qualities. Our extensive research indicates that aromatherapy diffusers which use heat, deliver the same health benefits as other types of aromatherapy diffusers.
Most all essential are steam distilled between temperatures of 130-190 Celsius:
The temperature in the heated essential oil pool in our Himalayan Salt Aroma Lamp aromatherapy diffusers never exceeds 125 degrees Fahrenheit (52º Celsius). The bulbs we use are for ovens so they are long lasting and not at all diminished by the heat. We use a hand blown, tempered glass container that is custom made for our Aromatherapy Diffusers.
Himalayan Salt Lamp Aromatherapy Diffusers
The Himalayan Salt Crystal Aroma Lamps offer the added benefit of negative ion generation. Fill the container half way with water and then add essential oil to fragrance a 10' x 10' room within minutes. As long as you keep it filled you can run it continuously. I keep one going in the inside stairwell of my home 24/7 because it also functions as a safety nightlight for when I'm on the stairs at night. When you want to change out the fragrance you just wash out the glass bowl with hot soapy water and then add your next oil. There is no water mist and no droplets of the oil to stain anything.
Candle-based Aromatherapy Diffusers
These units heat a dish containing essential oils with a tea light. Whatever oil you add needs to be mixed with at least 50% water. Comparatively, Tea light diffusers are simply not as efficient in controlling the temperature, because as the candle burns down the temperature will decrease. Controlling the temperature of the oil depends on finding the optimum distance between the flame and the glass holder. It is always a little tricky. Using an electrical bulb is better, because the heat is less and relatively constant. Never leave a candle unattended; tea light diffusers are not suitable if you want to diffuse scent in an unoccupied room.
Light Bulb Aromatherapy Diffusers
The light bulb ring diffuser is an easy and inexpensive way to use essential oils. Choose a favorite oil, place the ring on a low wattage bulb (for longer lasting aroma) and add the essential oil or essential oil blend of your choice. They are most often made of pottery and come in terracotta or white. While they are the most inexpensive they are also make the most mess. Excess oil can drip down the bulb into the light fixture. The more flammable citrus oils should never be used with larger and hotter light bulbs.
These diffusers pump air through a glass chamber filled with essential oils. They are driven by the same type of air pumps used in fish bowls. No matter how silent they are advertised, they tend to be noisy and vibrate. They can be okay around fish tanks, indoor waterfalls, or Jacuzzis where there is already noise. The glass is very fragile and in my opinion not suitable around kids and pets. The nebulizing diffuser uses no heat, and converts the essential oil into microscopic size droplets. However, due to the weight of these droplets, they don't tend to stay in the air for long periods of time. The small droplets of some of the essential oils can have a very harsh effect on lacquer finishes. The orange citrus and other dark oils will stain white or light colored drapes and bedding.
I'm a sucker for gadgets. Recently I purchased and tested a $130 diffuser that was advertized as "the most efficient and powerful essential oil nebulizing diffuser EVER made" and "whisper quite...silent." They also claimed that smaller particles stay suspended in the air for longer periods so you get more health benefits from less oil. It was just as loud as all pump driven diffusers, used the most oil of any diffuser I tested and dropped droplets of oil onto the white table cloth I tested it on. It also offered a quick change system that connects the essential oil bottle and the fish bowl type pump that but the bottle was easily knocked over. Like many other diffusers I tested, it featured an "advanced interval timer" to allow complete control of how long the unit is "On" or "Off" - a feature that I just never seem to use.
Micro Fan Aromatherapy Diffusers with Cotton Filters
A small fan blows air through a pad containing essential oils. Every model we tested where you put the essential oil on some type of pad dispersed by a fan tended to be messy. Eventually the cloth wicking material gets clogged. All the fans were noisy. Compared to the other types of aromatherapy diffusers, they put less scent into the room.
Ultrasonic Aromatherapy Diffusers
We found a couple that were both efficient room humidifiers and also did a decent job of dispersing some of the lighter oils like citrus, lavender, eucalyptus, etc. It also increases moisture in the room. In most cases that's fine, but not around fine wood furniture and most electronics. My favorite is made by Westinghouse. You can find it on-line for about $40. I would not try to use it on a room larger than 400 square feet. It has an 8.5 ounce reservoir that will run up to 16 hours.
These are probably still the most popular and least expensive. I bought a humidifier for $15 at Walmart which is relatively quiet and puts a lot of moisture into the room. However, the plastic is not designed to hold up to Eucalyptus and other essential oils.
Vaporizer or vapouriser is a device used to extract and deliver via inhalation the active ingredients of plant material, commonly cannabis, tobacco, or any of many other herbs. Vaporization is an alternative to smoking. Rather than burning the herb, which produces irritating, toxic, and carcinogenic by-products, a vaporizer heats the material in a partial vacuum so that the active compounds contained in the plant boil off into a vapor. I have not experimented with these.
You can still find the old glass vaporizers that were sold to dispense Vicks Vapor Rub. They work well with unguents (mixtures of essential oil in carriers of petroleum jelly or beeswax). They don't disperse pure essential oils as well as the new Ultrasonic or our Himalayan Salt Aromatherapy diffusers.