Light plays an important role in architecture. This paper aims to study how daylight impacts on the visual comfort and appreciation of space, human behaviour and the associated energy issues in the libraries of tropical Singapore. This study investigated the benefits of daylight as an important architectural component that interacts with human behaviour, enhances spatial quality and experiences with a special focus on how daylighting design principles and strategies could be applied to achieve a well-balanced luminous environment in terms of visual comfort energy consumption. This research project started with a detailed analysis of the architectural design concepts and daylighting design strategies of two libraries in Singapore followed by both qualitative and quantitative studies. Users’ subjective appreciations of selected spaces were collected through informal surveys. Field studies and digital parametric studies on daylighting performance were also undertaken. The associated energy saving potential of using daylight in libraries in Singapore is also discussed. The lessons learnt from this study form the base for developing design guidelines on daylighting design in libraries and energy saving in Singapore.