Is the Future Bright for LED Replacement Light Bulbs?

April 13, 2009 - Will we ever see an LED light bulb that can satisfactorily replace energy-wasting incandescent bulbs?

Last September, I wrote about the US Department of Energy (DoE) ENERGY STAR program to develop “user- acceptable” LED-based alternatives to incandescent lighting (see "Getting it Right ...the Second Time"). The DoE is determined not to repeat the past mistakes of their CFL lighting program, which initially resulted in the ENERGY STAR logo being associated with poor quality, oversized, unacceptable performance early CFL light bulbs.

To avoid this, the DoE’s initial LED lighting focus has been on luminaires that have advanced to a point where performance is equal to or better than traditional efficient lighting technologies, based on light output, luminaire efficacy, and cost. The recent ENERGY STAR Solid State Lighting Luminaire specification not only focuses on energy efficiency, but also specifies minimum light output (over a specified period of time), correlated color temperature (CCT), color maintenance, and a three year warranty! Since it went into effect last September, more than 25 luminaires have qualified to wear the ENERGY STAR logo. So, it appears the future is bright right now for LED luminaires.

But, are we any closer to the real prize, an LED light bulb that will replace the ubiquitous 60 W incandescent bulb for general area lighting? Anyone who’s recently purchased an LED “replacement” light bulb, popping up in retail shops (and the internet) everywhere, will probably answer no due to poor light output, uneven light distribution, and wrong color temperature.

However, this past January, the DoE distributed a proposed draft specification entitled ENERGY STAR Program Requirements for LED Integral Lamps (an integral lamp is defined as a lamp with LEDs, an integrated LED driver, and an ANSI standardized base intended to replace standard general service incandescent lamps of ≥ 25 watts, decorative (candelabra style) lamps, and standard reflector lamps of ≥ 20 watts). The proposed draft includes some no-nonsense specs, including the following for omnidirectional bulbs:

• Minimum luminous efficacy (55 lumens/watt)
• Minimum light output comparable to the target wattage of the lamp to be replaced (i.e. for a 60 W replacement, the minimum is 800 lumens)
• Luminous intensity distribution
• Maximum overall length (can’t be longer than the target bulb it’s replacing)
• Must be dimmable
• Three year warranty

This spec draft has generated a lot of stakeholder feedback. If you’d like to review the spec, feedback and get involved in the process, go to:
http://www.energystar.gov/index.cfm?c=revisions.ssl_luminaires

Back to my original question, there are some who believe LEDs are best suited to luminaires and will never be a serious light bulb replacement. As an eternal optimist, I think they will.

What do you think?