ABSTRACT
Advances in software and computer graphics mean that electric lighting design is increasingly computer-based, and handled by specialist consultants. Architects should note fresh demands of Building Regulations in this field. They should be aware of continuous gains in lamp efficacy, especially in connection with light-emitting diodes lamps. The efficacy of an electric lamp is defined as its luminous flux divided by the electric power consumed. Window design largely remains in architectural hands. Natural lighting has important implications for site layout and massing, and for energy conservation. Sunlight is increasingly important; solar geometry is the key to harnessing sunlight. Daylight factors remain significant, average values replacing traditional minimum requirements. Thermal applications of solar energy have long been recognised. The potential of sunlight, direct and diffused, in saving electrical energy by reducing the demand for artificial lighting, is less obvious. Decisions on siting and orientation may be more effective than later decisions on fenestration.
