Spatial Daylight Autonomy

The IES Daylight Metrics Committee recently published a new metric that describes very well “How much of “of a certain” space or building is adequately daylit?” [IES] Spatial Daylight Autonomy [THRESHOLD/50%] has been selected as the metric for analysis of daylight sufficiency. This metric means that a certain illuminance threshold has to be achieved at least 50% of the occupied hours to consider a space adequately daylit. This can then be reported as daylit area or a percentage of floor area that is daylight. The procedure has two advantages: On one hand it can provide significant information even if condensed to one number; e.g.”70% of the design variant’s area is daylit”. On the other hand it can also be used pointwise to directly highlight areas that are underperforming. This relates more directly to the built geometry.

Daylit Area Meshes

Daylit Area Tab