Illumination Levels in Interior Lighting

Measuring Light

• Light measurements can be expressed in foot candles or in the metric measurement called lux. Lux means lumens per square meter and gets used often to describe light levels. The LED Light Company describes a foot candle as the amount of light a birthday candle generates 1 foot away. One foot candle, or lux, each equals 1 lumen of light. A lumen is the equivalent of the light from 1 foot candle on 1 square foot of area.

Light Levels

• The level of sunlight outside on a sunny day is 10,000 lux. As a comparison, daylight in a room near the window would be 1,000 lux. For general activities, the indoor level of light should fall in the range of 500 to 1,000 lux. Office work or library study would require a level of 500 lux. A grocery store needs about 750 lux. For normal drawing work, plan on 1,000 lux. For very detailed drawing or mechanical tasks, figure on a range between 1,500 and 2,000 lux.

Mood Lighting

• Lighting affects the ambiance of a room, so manipulating the lighting can change the feel of a space. To create a cozy mood, use ambient light near the seating area. Use track lighting to focus on centerpieces. Arrange reading lamps close to the reader to increase light levels. The light from a fireplace or candles increases coziness. To create drama, put uplights under a plant to create leaf patterns on the wall. A narrow beam of light pointed downward on a vase or other object creates a striking effect.

Considerations

• Use a higher illumination level to accentuate stairs, exits and entry halls. Light draws more attention to the areas where movement is expected. Light can create an illusion of a larger space. A well-lit ceiling will appear higher. The color of the light can also influence how objects are perceived. Reddish or pink light gives the impression of warmth, and blue-green light will feel cool.