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Daylight factor measures indoor daylight availability as percentage of outdoor illuminance. It determines whether artificial lighting is required.

Formel

Daylight factor = (indoor illumination / outdoor illumination) × 100%

Steg-för-steg-guide

  1. 1Daylight factor = (indoor illumination / outdoor illumination) × 100%
  2. 2Values: <2% (supplementary lighting needed), 2-5% (adequate), >5% (well-lit)
  3. 3Depends on window size, orientation, obstruction

Lösta exempel

Ingång
Indoor illumination 100 lux, outdoor 5000 lux
Resultat
Daylight factor = 2% (borderline, likely needs supplementary lighting)
Typical office

Vanliga misstag att undvika

  • Over-sizing windows in climate with high cooling loads
  • Neglecting glare control in high daylight factor spaces

Vanliga frågor

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.

Redo att beräkna? Prova den kostnadsfria Daylight Factor-kalkylatorn

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