A Room-by-Room Guide for Ergonomic Lighting Levels

Ergonomics, as it relates to lighting, is basically having the right amount and location of lighting for what youre doing. In the workplace, it can be making sure computer monitors dont have too much glare on them (to prevent eyestrain) or ensuring that people performing tasks that require precision and fine-detail work have lighting on a path that ensures that there are no shadows cast on what theyre doing. In the home, having ergonomic lighting can mean installing task lighting above kitchen counters or a workbench or making sure that hallways and stairways have enough lighting in them for safety. Making Sense of Measurements Youll find light levels are listed in lumens, which is light output. Light intensity levels may be listed in lux or foot-candles (fc). Lux measurements are roughly  10 times a foot-candle measurement, as a foot-candle is 1 lumen per square foot, and a lux is 1 lumen per square meter. Incandescent light bulbs are measured in watts and may not have the lumen measurement on the packaging; for a frame of reference, a 60-watt bulb produces 800 lumens. Fluorescent lights and LED lights may already be labeled in lumens. Keep in mind that the light is brightest at its source, so sitting far away from a light will not provide you with the lumens listed on the packaging. Dirt on a lamp can cut into the light output as much as 50 percent as well, so it makes a real difference to keep bulbs, glass globes, and shades cleaned. Room Lighting Levels Outdoors on a clear day, lighting is approximately 10,000 lux. By a window inside, the available light is more like  1,000 lux. In the center of a room, it can drop dramatically, even down to 25 to 50 lux, hence the need for both general and task lighting indoors. A broad guide is to have general, or ambient, lighting in a passageway or a room where you dont perform concentrated visual tasks at 100–300 lux. Raise  the level of light for reading to 500–800  lux, and concentrate task lighting on your needed surface at 800 to 1,700 lux. For example, in an adults bedroom, you need lighting to be lower to wind down your body for sleep. In contrast, a childs bedroom may be where he or she studies as well as sleeps, so both ambient and task lighting would be needed. Similarly, in dining rooms, the ability to change the number of lumens through different types of lighting (ambient or over the center of the table) or dimmer switches can make the space more versatile, from an active area during the day to a relaxing space in the evening. In the kitchen, pendant lights above islands and range hoods with lighting over the stove are additional ways to use task lighting. The following is a list of minimum lighting levels for residential spaces. Kitchen General 300 lux Countertop 750 lux Bedroom (adult) General 100300 lux Task 500 lux Bedroom (child) General 500 lux Task 800 lux Bathroom General 300 lux Shave/makeup 300700 lux Living room/den General 300 lux Task 500 lux Family room/home theater General 300 lux Task 500 lux TV viewing 150 lux Laundry/utility General 200 lux Dining room General 200 lux Hall, landing/stairway General 100500 lux Home office General 500 lux Task 800 lux Workshop General 800 lux Task 1,100 lux