Vaporizers contain various forms of extraction chambers including straight bore, venturi, or sequential venturi, and are made of materials such as metal or glass. The extracted vapor may be collected in a jar or inflatable bag, or inhaled directly through a hose or pipe. With little to no smoke produced and cooler temperatures, less material is required to achieve a given level of effect. Hence, the irritating and harmful effects of smoking are reduced, as is secondhand smoke.
Precise vaporizers use an electric heating element, often featuring thermostatic temperature control.
Broadly, vaporizers may be classified by how they heat the substance:
- By thermal conduction
- By convection
- By thermal radiation
In conduction heating, the substance is placed on a metal plate that is then heated to release the active constituents. Conduction vaporizers were the first type to appear on the market, and are still in production.
In convection heating, the substance never touches a heating element. Instead, hot air passes through it, heating it rapidly, and allowing the release of the active constituents.
This method of heating releases more active constituents than conduction heating. Some convection vaporizers or vaporization systems use a hand-held heating wand with a glass-encapsulated element and vortex flow form inducing intakes, which when mated to a bowl on many common pipes or water pipes or when mated to a specialized vaporization chamber bowl, enable the user's draw to pull ambient air past a glass heating surface heating the air prior to its passage through the substrate in the bowl. The vapor is extracted and then passes through the pipe, often with water and/or ice for cooling and conditioning, and thence to the user.
Many convection vaporizers use a glass hand piece which contains the herbs to vaporize, with a long flexible drawtube (commonly called the "Whip") through which the user inhales the vapors. These units provide vapor from the herbs instantaneously. Some vaporizers have a bag or balloon attachment for storing the vapor for a period of time; vapor is blown into the bag, and the user detaches the bag and inhales the contents. Attachments can be placed between the vaporizer or bag and the user's mouth to cool the vapor with water or ice.
Convection vaporizers are either forced-air types which actively blow air through the heating element and herbs, or passive types, where the user inhales the air without the help of a fan or pump. Most vaporizers today use the convection principle, including heat guns, "wood box" types, and nearly every higher-end vaporizer available.
In radiation heating, the substance absorbs radiant energy and its temperature rises. The energy can be provided by a superheated thermal mass placed around it, or from a visible bright light source like the sun. Thermal mass radiation vaporizers permit uniform heating of substrate without diluting vapors, supplying high quality medicine. A pipe and a magnifying glass on a bright, sunny day can, with care and practice, act as an adequate radiation vaporizer.