What is "over-illumination"

n. 1 Excess light supplied beyond the amount required for a given task. 2 Wasted light through illumination of an unoccupied space, creating energy wastage. 3 Excessive or annoying light producing glare, annoyance and adverse health effects.

Over-illumination is the presence of lighting intensity higher than that which is appropriate for a specific activity. Over-illumination was commonly ignored between 1950 and 1995, especially in office and retail environments. Since then, however, the interior design community has begun to reconsider this practice. Over-illumination encompasses two separate concerns:

• Unnecessary electric lighting is expensive and energy-intensive. Lighting accounts for approximately 9% of residential electricity use and about 40% of commercial electricity use.

Over-illumination can be reduced by installing occupancy sensors, using natural sunlight whenever possible, turning off lights when leaving a room, or changing the type of lightbulb. Over-illumination does not refer to snowblindness, where high exposure to ultraviolet light causes physical damage to the eye. Too little light, the opposite of over-illumination, is associated with seasonal affective disorder.