Daylight, the primary light source in commercial and institutional buildings before the advent of cheap electric energy and air conditioning, is rediscovered as a replacement for nonrenewable energy. A review of the development of techniques for evaluating alternative daylight schemes to permit trade offs between the HVAC and lighting subsystems leads to life cycle costbenefit analysis as a desirable energy conservation criterion. Additional energy conservationcould be accomplished by utilizing daylight to reduce peak loads on electric utilities.