ABSTRACT
To evaluate lighting systems means to examine or carefully appraise them. Evaluating lighting systems is a multistep process. At the very minimum, the evaluation is a three-step procedure: performing a lighting survey or audit; identifying opportunities for improvements; and calculating savings and potential payback. Potential improvement opportunities may be identified on a quantitative or qualitative basis. Quantitatively, improvements can be measured and compared with standards of performance on the basis of power density (W/sf), illuminance (FC), and controls. Qualitatively evaluating improvements is a more subtle and highly subjective task, made easier by auditor experience. Qualitative lighting attributes include veiling reflections, glare, color and Color Rendering Index (CRI), lamp flicker, luminance ratios, and visual comfort probability. Savings may be calculated either as simple payback (SPB) or using life-cycle costing (LCC). Training and experience provide auditors with the skills they need to be good investigators and perceptive observers.
