The best essential oil diffusers are extracted from plants via a steam cleansing process and the result is highly intense oil that not only smells is very good, but can be used for numerous medicinal purposes. This means, no heating element, no concentration and your oils are dispersed in their purest form. The best essential oil diffusers can only give you relax and this ultrasonic Waves technology works on the vibration of the water at such a speed that it creates vapors, this is the technology that has revolutionized the way people use their aromatherapy. In heat diffusers, the required oils are heated to get diffused. Well, in that process, the user gets lovely aroma but healing properties of the oils are removed with heat. These diffusers are superb to spread the fragrance all through your home or office. But as far as the therapeutic properties of essential oils are concerned, heat diffusers are not at all effective. http://www.aromatherapy-oildiffuser.com/