Daylighting and Architectural Quality: Aesthetic Perception of Daylit Indoor Environments

Abstract

The present thesis concerns the field of daylighting in architecture. In particular, this thesis examines the topic of the aesthetic perception of daylit indoor environments. Most daylighting studies seem to use photometrical measurements to describe the light in a space. Moreover, most studies seem to focus on comparing metrics to establish an adequate illumination for optimal visual and task performance. However, lighting considerations should go further than merely visual and task performance guidelines; good lighting should also contribute to the aesthetic perception of any environment. This is an important distinction to establish: a room with enough light for performing tasks can be described as an ‘adequately illuminated room’, whereas a room that also provides a pleasant visual environment can be considered a ‘well-lit room’. Yet little literature investigating the aesthetic quality of architectural spaces lit by daylight can be found. Therefore, the present study seeks to explore how different daylighting designs affect the aesthetic perception of indoor built environments. The fields of architecture and daylighting are taken as starting points. In addition, the aesthetic perception of environments entails studies of environmental psychology, e.g. environmental aesthetics and measurement of environmental perception. Daylight and aesthetic quality are thus terms of paramount importance in the present research. In the scope of the work presented here, two types of daylighting design have been considered in the study: windows as the most basic daylight collectors in buildings (primary daylighting design), and daylighting systems as advanced measures to collect and distribute daylight deeper in interiors (advanced daylighting design). To examine the aesthetic quality of an architectural space, nine aesthetic attributes were selected: Pleasantness, Excitement, Order, Complexity, Legibility, Coherence, Spaciousness, Openness, and Spatial Definition. Considering that humans spend most of their waking time indoors, and that most of this time is spent at home and at the workplace, two small environments were the focus of the presented work: a student room and a single office unit. Experimental research using a mixed method approach was selected as the research strategy. Thus, two main experiments were carried out to investigate: i. the effects of windows on the aesthetic quality of a student room, where three different window sizes were considered in a room lit under overcast sky conditions; and ii. the effects of daylighting systems on the aesthetic quality of a small single office, where two types of venetian blinds and two types of light shelves were considered under overcast sky and clear sky conditions. The summarised results confirm that daylighting design (within the scope of the present research; i.e. daylight delivered by windows and/or daylighting systems) has a significant impact on the aesthetic impression of a small room. Moreover, the collective findings of the present work suggest that photometric measurements are not always the perfect predictors to judge the nine selected aesthetic attributes. Although photometric studies are necessary, other parameters not connected to lighting metrics (e.g. the location of light patches in the room and the physical and geometrical characteristics of the daylighting systems) impact the aesthetic perception of a small room and should be considered. Furthermore, the study presents a new experimental method that can be used in daylighting and aesthetics studies. This experimental method is based on the use of 3D or stereoscopic images of environments, taken with two cameras and projected full-scale on a silver screen. The method was tested in an experimental procedure and analysed using a method comparison statistical model. The findings show that stereoscopic imaging is a valid and accurate method for use in daylighting studies. Daylighting in relation to environmental aesthetics is still an incipient body of knowledge, as there is still much that we do not know. The aim of the presented work was set to shed new light on different aspects of daylighting studies, such as the aesthetics of a lit environment. The presented results provide new knowledge that could serve as a departure point for the development of new theories and assumptions that could improve the understanding of this interdisciplinary topic.