Is Human Centric Lighting Really Human Centric in a Classroom? : A holistic evaluation of a HCL-system in a classroom

Sammanfattning: The purpose of this study is to evaluate Human Centric Lighting in a classroom. Previous studies tend to focus primarily on the biological, non-visual, effects of the HCL. In this study, a more holistic approach to HCL is applied, including both the non-visual aspects as well as the visual and emotional aspects.   In order to fulfil the aim of the study, the three aspects - visual, emotional and biological - will be investigated through five different methodologies; observation and analysis of lighting distribution and behavioural analysis of lighting system as a visual aspect, surveys about the mood and emotions as an emotional aspect and visual performance and visual acuity as a biological aspect.   The evaluation took place in the elementary school Sturebyskolan in Stockholm, where a classroom with a HCL-system is to be found. The system includes three lighting settings; 800 lx, 6000 K (energy light/focus light), 500 lx, 4000 K (standard/normal light) and 300 lx, 3000 K (calm/relaxed light).   Results show positive effect on performance and better visual acuity in focus lighting than in relaxed lighting. Focus lighting was perceived as a cold and hard lighting for tests, while the relaxed lighting was perceived as a warm and calm lighting for a cosy feeling. The lighting characteristics are suited for a typical classroom. The ignorance of the lighting system can be a problem for the experience and usage of the lighting in the classroom.   In summary, to denominate a lighting system as HCL and only consider the altered colour temperature and light intensity is not comprehensive enough. A HCL-system needs to consider the visual, emotional and biological aspects, and the biological aspect is explicitly considered in this lighting-system, whilst the emotional and visual aspects are more ambiguously considered.   As a proposal to consider all three aspects, several layers of light could be added in order to strengthen the visual aspect and create a vivid and interesting atmosphere. Moreover, conscious arrangement of luminaires and luminaires with flexible characteristics could simplify and broaden the opportunities in the classroom and facilitate the use of light layers.