Currently, good quality LED products are fairly expensive, compared to standard lighting. But costs are coming down—in 2007, they were roughly one-seventh of costs in 2001—and it's expected that LEDs will be competitive within a few years.

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

Additional Resources

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