« Back to Glossary Index

What is Hot Start Time?

  The hot start time is the amount of time needed for an HID lamp to reach 90% light output after a brief power interruption.  

Why Don’t HID Bulbs Reach Maximum Light Output Right Away?

  HID lamps require time to warm up and generate enough heat to strike the arc. In most cases, the initial warm-up time for an HID bulb is somewhere between two and six minutes. The restrike time is often longer. When the lamp is switched back on after a short power interruption, the gases inside the bulb are too hot to ionize. “Restrike time” refers to the time required for the gases to cool and pressure to drop enough for the arc to restrike. This typically takes five to fifteen minutes. Then the HID lamp has to warm up to 90% output.