Words such as "halogen," "xenon" and "krypton" are thrown around to try to entice consumers, but few consumers understand what these terms really mean. Learning the difference between halogen bulbs, xenon bulbs and other types of electric lamps will help you make the best choice of lighting to fit your needs.
Both xenon and halogen bulbs are incandescent bulbs. Inside, they have a thin tungsten wire called a filament. Electricity flows through the wire, heating it up until it glows white-hot, producing light.
As the tungsten filament heats up, molecules from it begin to evaporate, slowly burning out the light bulb. Xenon and halogen bulbs have noble gases inside them. These gases have large molecules that deflect the tungsten molecules, slowing the rate of evaporation. This makes the bulbs perform better and last longer.
Xenon bulbs have xenon gas, the best-performing noble gas but also the most expensive. Halogen bulbs can have xenon, argon or krypton. Halogen bulbs also have a bit of iodine inside.
In most incandescent lamps, the tungsten settles on the surface of the bulb once it evaporates. In halogen lamps, the iodine serves as a catalyst, allowing some of the iodine to return to the filament and prolonging the life span of the bulb.
Halogen bulbs vary greatly depending on the gas in them. The best halogen bulbs are the ones with xenon inside. Plain xenon bulbs may be the second-best bet.