Light Emitting Diodes (LEDs) are part of a comparatively new class of lighting called Solid State Lighting (SSL). Unlike incandescent or compact fluorescent lamps (CFLs), LEDs are small electronic components that convert electricity into light.

LEDs are already being used in a variety of applications:

• Status lights on electronic devices of all kinds
• Flashlights
• Decorative lighting strings (both indoor and outdoor)
• Auto headlamps
• Traffic lights
• Outdoor lighting fixtures for parking lots, streets and parks
• Architectural lighting
• Retail display lighting
• Desk and task lights
• Home lighting applications such as recessed down-lights, and under-cabinet lights

LED applications allow for extraordinary flexibility in lighting design with regard to color, brightness, size, shape, and distribution.

However, in terms of general lighting—that is, general illumination using white light—quality and efficiency can vary greatly from product to product. The U.S. Department of Energy lists several reasons:

• The technology is new: LED technology is developing fast; new generations of LED devices appear every 4 to 6 months. Last year's LED light may well be outdated by now, with newer models providing better quality light more efficiently.
• The technology is different: Because LEDs are completely different from traditional lighting sources, new standards and testing procedures have just been implemented by the ENERGY STAR® program (a collaborative effort of the U.S. Department of Energy and the Environmental Protection Agency) as of June 2008 in the interest of making it easier for consumers to compare products.
• Everyone's learning: Because LEDs can be sensitive to some thermal and electrical conditions, manufacturers are racing to develop fixtures or components that are LED compatible in multiple applications.

Ongoing research in LED lighting is happening right now all around the world. Governments and private industry are extremely interested in LEDs both because of their great adaptability in design, and because of the potential energy savings that LED lighting offers. LED lighting will revolutionize home, office, retail, and architectural lighting in the coming years—and that includes general white-light illumination.

Source: UF/IFAS Energy Efficient Homes: Introduction to LED Lighting, Barbara Haldeman, Wendell A. Porter, Kathleen C. Ruppert, 2008.

Additional Resources:

EnergyStar®  - http://www.energystar.gov/

UF IFAS Energy Efficient Homes: Introduction to LED Lighting - http://edis.ifas.ufl.edu/FY1049

Using LEDs for General Illumination http://www1.eere.energy.gov/buildings/ssl/using_leds.html

Solid State Lighting Luminaires http://www.energystar.gov/index.cfm?c=new_specs.ssl_luminaires

LEDs http://www.lrc.rpi.edu/researchAreas/leds.asp

LED Lighting http://www.toolbase.org/Building-Systems/Electrical-Electronics/white-LED-lighting

Introduction to LED Lighting - http://lightingdesignlab.com/articles/LED_fund/intro_ledfund.htm