Combined impacts of glazing types and dynamic LED lighting on human centric lighting requirements

As modern offices increasingly integrate smart lighting systems, understanding their combined impact with daylight on human well-being is essential. This study aims to examine how glazing properties and dynamic LED lighting jointly influence circadian metrics, cognitive performance, and subjective evaluations in office environments. An experimental methodology was applied, combining lighting measurements, circadian calculations, cognitive performance tests, surveys, and statistical analyses. Results show that illuminance below 300 lux failed to meet circadian thresholds, while levels above 750 lux enhanced circadian activation, comfort, satisfaction, and mood. Optimal visual performance occurred at 300-750 lux, and LED colour temperatures between 4000 and 5000K yielded the highest circadian-effective values, supporting faster cognitive processing, better memory, and greater comfort while reducing glare and sleepiness. Glazing analysis revealed that tinted and photovoltaic types substantially altered indoor spectrum and attenuated circadian support, whereas clear and neutral low-e glazing preserved spectral balance. Interaction effects confirmed that both light intensity and spectrum must be considered together to achieve biological and perceptual benefits. Demographic influences were minimal, and useradjustable LEDs further enhanced comfort and satisfaction. This study provides novel evidence on the integrated role of glazing and dynamic lighting, offering practical guidance for office design that balances energy efficiency with occupant health, comfort, and productivity.