Heat dissipation n overheating - T5 vs LED!!!

[CY2010]

As subject states, this is part of the report which has drawn my attention to the heat concern on LED. It says that as compared to T5, LED's overheating has much concerned. I'm abit confused now as what I heard so far is LED generates much less heat than MH n T5.

Any expert can clarify this...

Here is the report mentioned n the link: http://lumiversal.net/upload/T5%20v.%20LED.pdf

The case study by IEEE also examines the heat dissipation of each lamp and found that the T5 lamp dissipated about 73% of its total lamp power as heat. However, the LED lamp in this study dissipated about 87% - 90% of its input power as heat. This high heat dissipation percentage can greatly increase additional cooling costs in your building, significantly reduce bulb lumen life, and lead to possible bulb failure.

LED fixture heat dissipation and overheating is a growing consumer concern. An Illumra Green Systems executive recently discussed this issue in an article entitled “The Biggest Barrier to LED Lighting.” In this article, the author suggests LEDs have the potential to double their temperature after they have been in use for an extended period of time. The resulting increased LED temperature can reduce the lamp’s life hours by more than 50%. The author describes why LEDs are more prone to overheating than fluorescent bulbs by stating,

“Most light fixtures have been designed to take light from a (fairly focused) point source, the filament in the bulb, and diffuse it evenly over a space. Putting lots of LEDs at one point concentrates the heat, making it harder to keep the LEDs cool.”

To prevent heat concentration in an LED fixture and avoid LED bulb failure, users must provide additional system cooling, resulting in higher HVAC costs and greater energy use.

[sherman]

All light the heat dissipated is all round.

For LED heat is dissipated upward only.