Advanced energy-efficient lighting systems: Progress and potential

From a systems perspective, energy-efficient design should strive to minimize the energy and money required to provide the desired quantity and quality of illumination. A wide spectrum of technologies, design practices, and control strategies exists to increase lighting energy efficiency. We describe the state of the art in energy-efficient lighting (emphasizing field operating conditions rather than product test results) and give an overview of its benefits. We consider existing and emerging lighting components: lamps, ballasts, fixtures, controls, and design issues as well as other building systems and features with which lighting interacts, including HVAC systems. Estimates of the societal cost-effective potential savings from improving lighting energy efficiency range from 50 to 80% of direct lighting energy use in developing and industrialized countries.