Presentation from the 8th VELUX Daylight Symposium that took place in Paris on 9 October 2019.
For more information please visit thedaylightsite.com & www.velux.com/veluxdaysinparis
ABSTRACT
*This talk presents findings from the doctoral dissertation \Perceptual effects of daylight patterns in architecture", conducted
by Kynthia Chamilothori at the Laboratory of Integrated Performance in Design (LIPID) in the Ecole polytechnique federale
de Lausanne (EPFL), under the supervision of Prof. Marilyne Andersen and Dr.-Ing. Jan Wienold.
Daylight is a driving factor on how occupants experience space, a quality which is widely recognized in architecture. Similarly, lighting research has demonstrated the positive perceptual effects of sunlight penetration on occupants, such as an increased sense of well-being and the creation of visual interest in the space. However, little is known about the perceptual effects of the spatial distribution of daylight, and about how the geometry of a facade
and the resulting daylight pattern in a space can affect its occupants. Furthermore, we have limited knowledge
about how the space function influences the appraisal of lighting conditions.
This talk will demonstrate that the facade geometry and the resulting daylight pattern, as well as the space
function, matter in how occupants perceive a space. Specifically, we will present two experimental studies with
72 and 265 participants, respectively, that investigated responses to variations of facade and daylight conditions
across different scenarios of space use. Participants were immersed in virtual reality (VR) interior scenes with facade
configurations of an equal perforation ratio and varying spatial composition of openings. This work introduces two
novel methodological contributions: the use of VR as an experimental tool, and the collection of physiological data
as a complementary measure to questionnaires.
The first study investigated subjective and physiological responses of participants across three facade geometry
variations under clear sky, for two scenarios of working and socializing in the space. Results reveal that the facade
and daylight composition significantly influenced both the participants' subjective responses and their mean heart
rate. The space function affected the appraisal of the facade and daylight geometry variations, highlighting the
importance of considering this factor in facade and lighting design, while challenging the use of prevalent shading
system designs {such as venetian blinds{ in non-working environments. Furthermore, the significant influence of
facade and daylight composition on participants' mean heart rate has great implications for architecture, showing
that a simple change of shading system {from venetian blinds to an irregular distribution of openings{ could induce
not only subjective but also physiological responses to occupants.
Building on these highly positive results, a paper-based survey was conducted to identify facade variations with
great potential to affect occupant perception, according to architects. These variations were then used in the
second experimental study to investigate the effect of facade and daylight composition on occupant subjective
responses, combining facade variations, sky types, and space function in VR. In addition, this study was repeated
in different European countries to examine regional differences in participant responses. Results demonstrate that
the spatial composition of facade and daylight patterns significantly influenced how the space is perceived (Figure
1). Moreover, significant effects on participant responses were found both for the function of the space and for
regional differences, highlighting the importance of these factors for lighting research. The findings presented in this
talk demonstrate that facade elements and their interaction with daylight have a quantifiable effect on occupants,
and open new research directions in the intersection of the fields of architecture and lighting.
Kynthia Chamilothori is an Assistant Professor in the Human-Technology Interaction group at the Eindhoven University of Technology (TU/e). She received her PhD in Architecture from the Laboratory of Integrated Performance in Design (LIPID) at the École polytechnique fédérale de Lausanne (EPFL) in 2019, and her Master's degree (Dipl-Ing) in Architectural Engineering from the Technical University of Crete in 2014. Her research interests lie in the intersection of lighting, architecture, human perception and wellbeing, with a particular focus on how the characteristics of light in space can influence the subjective and physiological responses of occupants.