Evidence Domain

Lighting Design

What it studies

Light in human environments: illuminance, glare, daylight, spectral quality and — in its biological branch — light's non-visual effects on alertness and circadian timing. It spans firm engineering (task lighting, glare control) and an evolving biological literature (circadian-effective light).

Why it matters

Daylight access is among the most consistently valued workplace attributes in occupant research, and task-appropriate lighting is basic visual ergonomics. The circadian dimension adds a genuine but frequently oversold layer: light demonstrably affects alertness and circadian timing, while workplace-specific outcome claims (productivity percentages, health guarantees) typically outrun the field evidence.

Questions it answers
  • What lighting does each setting's task profile require?
  • How should daylight access distribute across the floorplate and its populations?
  • What does circadian-effective lighting evidence actually support in workplace application?
  • Where do glare and screen-work conflicts arise?
Evidence sources
  • Lighting standards (EN 12464-1) and visual ergonomics research
  • Daylighting research and occupant preference studies
  • Circadian photobiology (strong on mechanism, developing on workplace outcomes)
  • WELL and similar frameworks (read as consensus guidance, not primary evidence)
Design and policy implications

Daylight distributed as an equity question, not a seniority perk; task lighting specified per setting class; glare control designed for screen-dominant work; circadian-informed specification where adopted, stated at the strength the evidence bears.

Related methods
Common misuse

Circadian inflation: laboratory photobiology converted into workplace productivity guarantees. The honest position — light matters, daylight is valued, biological effects are real, precise workplace outcome claims are premature — sells worse and holds up better.

Further research

Field studies of circadian lighting interventions in real workplaces are the missing evidence layer; most current guidance extrapolates from controlled settings.