High power LED diodes are lights producing high amounts of heat. But the amount of electrical energy converted to heat is much smaller than other light sources. On the thermal picture below you can see a comparison between NGL LED light and compact fluorescent light (CFL).
When we are developing LED lights it is very important that we have good thermal management. The thermal management prevents LEDs from overheating and provides low junction temperature. Recommended junction temperature for high power LEDs should be under 85°C. If the temperature is higher the life span, efficiency, luminance and reliability of LED diodes is decreased. Low quality LED diodes can reach temperatures around 190°C. The life span of those LEDs is questionable.