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Daylight factor measures indoor daylight availability as percentage of outdoor illuminance. It determines whether artificial lighting is required.
Formule
Daylight factor = (indoor illumination / outdoor illumination) × 100%
Guide étape par étape
- 1Daylight factor = (indoor illumination / outdoor illumination) × 100%
- 2Values: <2% (supplementary lighting needed), 2-5% (adequate), >5% (well-lit)
- 3Depends on window size, orientation, obstruction
Exemples résolus
Entrée
Indoor illumination 100 lux, outdoor 5000 lux
Résultat
Daylight factor = 2% (borderline, likely needs supplementary lighting)
Typical office
Erreurs courantes à éviter
- ✕Over-sizing windows in climate with high cooling loads
- ✕Neglecting glare control in high daylight factor spaces
Questions fréquentes
Does orientation affect daylight factor?
Significantly; south-facing windows get stable light, north-facing less direct but more diffuse.
How do you improve daylight factor?
Increase window area, use reflective interior surfaces, reduce obstructions, add skylights.
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