Thursday, October 22, 2009

Comparative Study on the Thermal Performance of LEDs and Fluorescent Lamps

A study on the issues facing LED lighting in general illumination lighting has been published in "IEEE Transactions on Power Electronics - Vol. 24 No. 7". Authored by in part by Dr. Ron Hui - IEEE Distinguished Lecturer PELS. This study states that despite claims of high efficacy, LED output performance is only true at low junction temperatures and not sustainable at high temperatures (which is the normal operating environment for many general illumination lighting applications). The study refers to the need to identify the “hidden issues” associated with LED lighting. A surprising number in this study was that while linear fluorescent tubes dissipate between 73%-77% of total lamp power as heat - LEDs dissipate 87%-90% of input power as heat.

This supports what we have been hearing from the LED industry - that LEDs will only be a viable solution in general illumination lighting when consumers and businesses are willing to install new LED specific lighting fixtures.

This report can be acquired at:

A Simple Method for Comparative Study on the Thermal Performance of LEDs and Fluorescent Lamps
Yaxiao Qin Deyan Lin Hui, S.Y.
Dept. of Electron. Eng., City Univ. (CityU) of Hong Kong, Kowloon, China;
This paper appears in: Power Electronics, IEEE Transactions on
Publication Date: July 2009
Volume: 24, Issue: 7
On page(s): 1811-1818
ISSN: 0885-8993
INSPEC Accession Number: 10812269
Digital Object Identifier: 10.1109/TPEL.2009.2017021
Current Version Published: 2009-07-28


A simple method is proposed to measure the heat dissipation of LEDs and fluorescent lamps in an open system that allows light energy to escape. Based on this method, a comparative study on the thermal and luminous performance of high-brightness LEDs and fluorescent lamps is presented. At rated power, T5 and T8 fluorescent lamps generate about 73%-77% of their total power as heat, while three types of high-brightness LEDs dissipate about 87%-90% of input power as heat. Heat dissipation is an important factor particularly for air-conditioned buildings when overall energy efficiency is considered. T5 fluorescent lamps perform better than some existing LEDs in terms of luminous efficacy and heat generation in this study.