Daylight　has　two　characteristics:　radiometry　and　photometry.　Hong　Kong　is　situated　just　south　of　the　Tropic　of　Cancer　and　receives　a　lot　of　daylight　which　could　generate　more　lighting　energy　savings　but　bring　solar　heat　gain　at　the　same　time.　This　study　appealed　that　the　energy-efficient　design　should　guarantee　residents＇　luminous　comfort　level　first.　A　dynamic　daylight　metric,　average　DA300　(Daylight　Autonomy),　was　first　tested　to　quantify　occupants＇　luminous　comfort　by　using　statistical　analysis　with　the　data　from　questionnaire　survey　and　climate-based　simulation　of　108　unit　cases.　The　benchmark　of　Ave.　DA300　is　then　found　as　29.6　%.　A　new　parameter　EDR　(Energy　Daylight　Rate)　was　also　proposed　to　reflect　the　relation　between　daylighting　performance　and　energy　performance.　Case　study　was　conducted　to　optimize　the　green　features＇　design　and　validate　the　utilization　of　EDR.　The　result　showed　the　EDR　could　help　optimize　the　envelope　design　at　the　early　stage.　(c)　2017　The　Authors.　Published　by　Elsevier　Ltd.