Surface Reflectance vs. Indirect Lighting Illuminance

Indirect ceiling cove lighting bathes the ceiling in a soft, ambient glow. The reflectance and finishes of the ceiling and walls impact the efficiency of this lighting method. Lighter finishes enhance reflected light, leading to increased illuminance on the floor. Additionally, a ceiling with a greater offset distance from the cove ensures a smoother lighting effect across the surface. It’s advisable to avoid a glossy ceiling finish to prevent the mirroring effect of luminaire images.

Note: In these studies, the indirect cove lighting was 1 ft away from the ceiling. Increasing this distance can further enhance the evenness across the ceiling.

Study Results (Floor Reflectance 0.2)

Ceiling 0.8, wall 0.8: avg 36.5 fc at floor

Ceiling 0.8, wall 0.5: avg 29.9 fc at floor

Ceiling 0.8, wall 0.2: avg 25 fc at floor

Ceiling 0.5, wall 0.8: avg 27.9 fc at floor

Ceiling 0.5, wall 0.2: avg 19.9 fc at floor

Ceiling 0.2, wall 0.8: avg 20.5 fc at floor

Ceiling 0.2, wall 0.5: avg 17.5 fc at floor

Ceiling 0.2, wall 0.2: avg 15.2 fc at floor