Diffusers

An ultrasonic diffuser disperses pure essential oil into the air as a fine mist, using water and high-frequency vibration. It is the most common way to use aromatherapy at home - quiet, inexpensive to run, and it adds a little humidity to a room.

Three to five drops is enough for an average bedroom or living room. More is not better: past a certain concentration the nose stops registering the aroma at all, and you are simply using up oil. Run a diffuser in bursts of 30 to 60 minutes rather than continuously. There is no benefit to running one all night in a closed bedroom.

Match the diffuser to the room. A small desk unit is right for focus oils at work; a larger reservoir suits a living room. Portable and car diffusers cover everything in between.

Clean the reservoir regularly - oil residue builds up, goes rancid, and will make a good oil smell bad. Browse essential oils to diffuse, or read the diffusion guide.