Vaporizers are used to heat dry herb or extracts to the point of vaporization, but not to the point of burning. They do this by controlling the internal temperature of the heating chamber electronically, allowing you to enjoy the vapour without having to worry about the carcinogens that come with combustion.
Conduction & Convection
Vaporizers normally use one of two main heating systems: conduction or convection.
Conduction vaporizers heat substances directly using a conductive substance, like metal or ceramic. In these types of devices, the substance normally sits atop of the heating element, and the heat is administered like a pot or frying pan on a stove. Without stirring, the heat transfers only to the substance that it is touching, so this may lead to some uneven heating. Some herbal vaporizers, and the majority of extract vaporizers, use this heating method.
Convection vaporizers heat substances indirectly, often using heated forced air passing through the chamber to heat the herb to the point of vaporization. Convection vaporizers often provide the most even heating and don’t require stirring, as the heat is transferred uniformly throughout all of the substance. Higher-end herbal vaporizers are most likely to use a convection heating system.