Economically sustainable for LED
LED light bulbs could be a cost effective option for lighting a home or office space because of their very long lifetimes, even though they have a much higher purchase price. The high initial cost of the commercial LED bulb is due to the expensive sapphire substrate which is key to the production process. The sapphire apparatus must be coupled with a mirror-like collector to reflect light that would otherwise be wasted.
During this transition period, it is a challenge to ensure that this technology is used where it is most appropriate and effective, and to avoid poor-quality products damaging the reputation. 2009 DOE testing results showed an average efficacy of 35 lm/W, below that of typical CFLs, and as low as 9 lm/W, worse than standard incandescents. It is a challenge to get buyers and users to be conscious of and make decisions based on life-cycle costs instead of the more obvious initial purchase price, and to avoid having low-efficiency products ride on the coattails of hype generated by lab test results.
In 2008, a materials science research team at Purdue University succeeded in producing LED bulbs with a substitute for the sapphire components. The team used metal-coated silicon wafers with a built-in reflective layer of zirconium nitride to lessen the overall production cost of the LED. They predict that within a few years, LEDs produced with their revolutionary, new technique will be competitively priced with CFLs. The less expensive LED would not only be the best energy saver, but also a very economical bulb.