Energy-efficient lights have replaced incandescents in many energy-efficient homes. In most cases, incandescents are simply replaced with energy-efficient lights having an equivalent light output. But that's not always the case. Because energy-efficient lighting uses fewer lumens per watt, there's a temptation to use higher light levels in certain areas. This is understandable, but the extra light doesn't always help people see better. The eye adapts to very low light levels (moonlight is less than 1 footcandle) and very high light levels (a sunny beach can be over 20,000 footcandles), but it only adapts to one light level at a time.

Take the case of an entry. Entry lighting is supposed to light the way to a door at night. But if the entry is over-illuminated, the resulting glare will make walkways or stairs leading to the entry appear darker than they should. That's because it takes the eye longer to adapt from the bright entry to the darker walkway. To compensate, you may be tempted to install brighter lights along the walkway, which means you've lost much of the benefit of the efficient lighting.

If you need more light in your entry, a better strategy is to use two or more low-level light fixtures instead of one very bright fixture. This lets you put the light on doorways, stairs and other critical areas while maintaining a low but uniform light level. A contrast ratio of less than three-to-one between nearby fixtures will let you softly accent a particular area without creating glare.

Cost Issues

Another consideration when lighting an entry is cost. While it's tempting to emphasize first costs and ignore the much higher life cycle cost of a light source, this strategy is pound foolish. For example, a 300-watt halogen flood light may cost $10 to buy, while a 22-watt compact fluorescent lamp costs $30. But if the fixtures are on ten hours a day, they have an annual operating cost of $6.92 for the CFL and $63.70 for the halogen! This example is based on $.05/kWh. Without careful planning, you could end up paying more for poor lighting.