When the ballast ignites, it takes in a small amount of power and creates an intense charge of electricity across the electrodes. This electrical charge excites the gas molecules inside the bulb and causes them to discharge photon particles, producing light. Because the light is based on this gas discharge, HID lights only produce about 5% of their total output at ignition and can require up to 30 seconds to warm up to full power. If the light is turned off, it must cool to a certain temperature before it can be re-ignited.

This process creates several significant advantages over a standard light bulb. Because heat not a necessary component of light production in HID lights, they are able to produce the same or even more light at a much cooler temperature. HID lights are also far more efficient because the electrical current is only the catalyst for the gas to discharge its light particles, not the primary source of heat and light. The ballast regulates a constant flow of power only to keep the gas molecules excited, while a standard light requires a constant intense electrical current to keep the filament hot. HID bulbs will last longer than standard bulbs because of the rapid decay of the tungsten filament and will also produce more light toward the end of its life.

In addition to being more efficient, HID lights also produce brighter and more intense light because the entire capsule of gas is used instead of just a small filament in the middle of the bulb. This also means that the light will be distributed more evenly than with a standard bulb