In the past, property owners and managers have tackled the need for better outdoor lighting by installing HID (high intensity discharge) lighting sources that essentially blast the grounds with light. Unfortunately, high intensity lighting typically casts hard shadows, produces an unnatural look, and distorts color, while adding significantly to the monthly electric bill.

In other words, the quantity approach to outdoor lighting completely ignores the quality aspect. Light, after all, has a very specific purpose. Tenant security in parking areas, walkways, outdoor seating or recreational areas is a primary concern. So is the aesthetic quality of light, which can make a property more attractive to prospective tenants. Both issues impact occupancy rates, and ultimately the bottom line.

Yet, light quality has largely been misunderstood, in particular how the human eye reacts to light. In the absence of this information, light meters have been used to ascertain quality, but there is considerable data that now shows that light meters “see” light differently than the human eye. Therefore, a better understanding about the physiology of vision is casting new light on which lighting technologies work best.

Seeing Better

Most HID light comes from a point source, and hence, creates hard shadows. The physiologic consequences can be quite unnerving, as the harshness of this light forces the iris to contract, which subsequently causes a “disability glare” that can register as discomfort or even pain.

Instead, by taking into account the human visual response and applying this information to outdoor residential, commercial, and industrial lighting designs, visual acuity can be improved through a combination of fluorescent light sources within carefully designed fixtures.

“We do not want our residents to worry about their surroundings, and we accomplish this by using efficient lighting around our buildings,” says Seth Greenberg, CEO of Engineered Concepts, Inc., Marietta, GA, a real estate firm that specializes in the development and management of multifamily properties. “When our lighting fixtures shed a natural and appropriate light, then people feel more comfortable and safety is no longer an issue for them.”

Fluorescent light emanates from a tube that disperses light throughout its length. This dispersion helps reduce hotspots and the sharp “fall-off” that creates shadows. This “soft fill” light allows for a uniform visibility."

“The quality of light is its trueness to the daylight that we see with our eyes,” explains Leetzow. “The human eye has three photoreceptors, red, blue and green, just like computer displays and televisions. When combined, the red, blue and green light frequencies make white light that enables people to see more normally.

Because properly designed fluorescent fixtures and lamps require fewer lumens to produce higher quality, whiter light, they also require substantially less energy. ❑