All high power LEDs produce heat as a by-product of lighting and must be properly cooled to ensure long life and reliability. You cannot run high power LEDs without ensuring that the junction temperature (the core temperature of the LED) is kept below it's maximum temperature rating.
Failure to keep the LED properly cooled will result in:
- Significantly shortened life.
- Reduced light output.
- Change in color output. (Especially with white LEDs)
- Complete LED failure.
To help you select a suitable heat sink, we have put together this information page and heatsink calculator.