Daylight autonomy

DL-Light calculates Daylight Autonomy in natural light and shows how many hours per year the project do NOT need artificial lighting.

DL-Light also allows to calculate directly BREEAM requirements or custom criteria.

The Daylight Autonomy indicator has been created to evaluate the performance of projects regarding natural light using a minimum illuminance level to maintain. It is also used to quantify the artificial lighting consumption necessary to maintain that illuminance level.

The analysis of Daylight Autonomy starts with the idea that, when there is enough natural light, then artificial lighting is not used. Hence, the calculation is performed using an illuminance threshold, usually 300 or 500 lux and occupancy profiles for the spaces.


Ray-tracing simulations hour per hour are performed and results are compared to the pre-defined illuminance thresholds to calculate results on the basis of climatic data for the site, the 3D model and material characteristics.