Sciencegasm!

[tw]

Originally Posted by BigV

I admit I have not made any household incandescent/fluorescent to led switchovers yet, but that has been mostly for cost reasons. But just as I have made the change from incandescent to fluorescent in the house as the cost per bulb has fallen, I expect to make another change when the led bulbs become reasonable.

You have not done it because it does not yet exist economically. From Electronics Design Magazine of 9 April 2009:

The Department of Energy is offering a prize of as much as $10 million to create the first solid-state replacement for the 60 W incandescent light bulb ... "

Sylvania recently offered one for consideration. Reliability still remains a problem.

LEDs have a 100,000 or 50,000 hour life expectancy. Life expectancy and efficiency numbers that fall quickly with higher power ratings. A low power LED would typically do 90 lumens per watt. A 100 watt incandescent bulb is 1500 lumens. A 20 watt compact fluorescent at 1500 lumens is 75 lumens per watt. LEDs at these lumen levels still are not competitive with compact fluorescent. A 180 watt sodium lamp is 27,000 lumens - or 150 lumens per watt. LEDs have a long way to go.

Now for history. No matter how many advances are made, we routinely spend 0.72% of GDP on lightning. Lights with greater efficiency did not mean less energy use. But it does mean an economic increase in productivity. How great? Varies significantly. Advances dur to LEDs (productivity increases) would be greatest in Africa. But the idea that LEDs will decrease energy consumption contradicts the lessons of history.

What factors cause lighting energy reduction? Increases in cost of energy or a reduction of living standards.