in recent years, LED has been constantly advocated as being the high energy efficient and lifelong lamp. a comparison of the led lamps to compact fluorescent (both revolutionary energy efficient lamps) of equal lumens package, shows that the annual electrical operating costs will be decreased by almost 2.5 times by switching to led. although there has been several positive comparative studies that promote led lamps, one needs to consider the below before labeling it as an environmentally friendly light source. heat sinks used with LEDs are designed to absorb and disperse excess heat away from the LED diode and into the heat sink. too much heat will damage the LED phosphor, resulting in lower light output, changes in color and or a significant decrease in life expectancy. for a LED lamp to be more energy efficient you need to dissipate the heat properly by making the heat sinks bigger (more aluminum). however, looking closer at the constituents of the aluminum material, it shows that 80% of it is virgin aluminum, and only 20% is recycled! as well, aluminum processing creates a range of waste products, the most significant being mercury emission, which is solid airborne elementary mercury release. in fact, the production of one tonne of aluminum leads on average to 16.5 tonnes of greenhouse gas emissions. the energy intensity required to produce a tonne of aluminum is 14,289 kWh. LED modules require a driver to operate. till this date, there is no program of recycling the electronics of the LEDs. many LED drivers exhibit poor power factor and/or poor harmonic power factor. this comes from low cost driver design. poor power factor results in added electrical system losses. the quality of the white light (having high CRI values) is inversely proportional to the efficacy (lumens per watt) of the source, thus higher efficacy means having a poorer quality of light. LED light does have an abundance of blue light wavelengths. there are many findings by the international dark-sky association (IDA) that show that light sources rich in blue wavelengths brighten the night sky more than any other color. they also suppress the secretion of melatonin, a hormone that influences circadian rhythms (natural body cycles). this has many harmful effects on the human health and wildlife. all things considered, one should be very selective with the quality of LED products they select to avoid having the above negative aspects.