IES LM-83-23

This document describes two annual daylight performance metrics, spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE), which provide two useful dimensions for evaluating daylight performance. Both metrics are generated via a similar computer-based simulation methodology that uses a full year of hourly weather data to calculate illuminance values inside a given architectural space. The sDA metric is distinguished from many others in that it explicitly
accounts for the movement of operable shading devices at daylight apertures, which hereafter in this document will be collectively referred to as blinds.