Lighting for Results
The goals of any interior retail lighting system are often the same: to attract and guide customers, to help them evaluate merchandise and to assist them in quickly and easily completing the sale. If done correctly, lighting has been proven to increase merchandise sales.

The Guiding Light
While lighting must attract customers to the retail space, it must enable customers to read signage and move throughout the store. The quantity and quality of the illumination will create a lasting impression and will help customers decide whether they want to return to the store in the future to shop.

The Buying Decision
Customers will not make a purchasing decision until they have the opportunity to evaluate merchandise and determine its specific attributes, such as color, texture and quality.
Illumination must be sufficient so customers can read price tags and all labels. In facilities such as clothing stores, the lighting must be sufficient in sales areas and dressing rooms so customers can see how the items look before they purchase them.

It’s a Sale!
The lighting within a store must facilitate customer transactions. Once customers make a final decision, they must be able to easily locate the sales register. The lighting should also help sales personnel quickly ring up the sale, scan credit cards and wrap packages. Good lighting will help minimize returns since customers can fully evaluate merchandise in the store and are less likely to be disappointed with their purchases later.

Design
Considerations
A well designed lighting system does more than provide sufficient footcandles. It considers all of the elements within the space and uses the most appropriate luminaires and lamps to create a comfortable and highly visual environment.
Table 1; on page 17 compares the importance of design considerations to types of retail spaces.

Lighting Uniformity
Customers will feel comfortable in a uniformly lit environment because they can view the merchandise and discern details. Most retail environments will benefit from some degree of uplight, which promotes uniformity by reducing the contrast between the light source and the surrounding area. A system with uplight will improve the luminance of vertical surfaces, such as signage, and will minimize shadows and glare.

(80-100 percent uplight)
Luminaires with this type of light distribution are ideal for spaces that demand maximum uplight. When a large quantity of light is bounced off the ceiling, the result is a diffuse illumination that creates an open and airy environment.

(40-60 percent uplight)
An almost equal balance of uplight and down-light supplies high levels of illumination on floors and display areas while allowing a certain amount of light to bounce off the ceiling. Type 50 luminaires are great for large areas where retailers want a simple, yet high-quality and efficient lighting system.

(20-40 percent uplight)
Type 30 luminaires focuses customer eyes on the merchandise, yet provide enough uplight to prevent a dark and gloomy ceiling. They enhance the aesthetics within a space and bring out the true colors of merchandise while emphasizing texture.

(0-20 percent uplight)
When maximum levels of illumination are needed for a specific task, such as alterations, a type
10 is the best solution. Light is focused on the task enabling easy visibility

Color Rendering and Temperature
Color is a powerful merchandising tool. Shoppers must be able to determine the exact colors of merchandise—whether they are selecting clothing, furniture, automobiles, packaged goods, or food.
Color rendering is the ability of the light source
(the lamp) to represent the true colors in merchandise. The closer the color rendering index (CRI) is to 100, the more natural and vibrant colors will appear.
The lamp’s color temperature must be considered since it determines whether the environment appears yellowish and warm or bluish and cool.
The correlated color temperature (CCT) is measured in Kelvin (K), with a higher CCT
(4,000K) appearing cooler or blue, and a lower CCT (3,000K) appearing warmer.
A warmer feel enhances skin’s color and works for many areas within a grocery store, such as the meat counter. A cooler environment enhances the appearance of clothing and produce.

Noise
It is imperative that retail stores are comfortable to shop in, including background noise. A ballast that hums or music that is played too loud is disturbing to a customer. They will choose not to spend much time in that store.
Electronic ballasts and potted ballasts are virtually noise-free allowing the customer to concentrate on the merchandise, not the noise.

Daylighting
Daylight adds another dimension to the overall lighting design and can impact customers’ perception of the space. The amount of daylight that comes into the store should be controlled.
Daylight can be controlled through thoughtful architectural design and window treatments.
Electronic lighting controls are also available that allow stores to take advantage of daylight while creating a more visually exciting space. The Prismatron® electronic Daylight
Harvesting™ ballast from Holophane, for example, facilitates harvesting through automatic, full range dimming, allowing the light level to be controlled while providing energy savings.

Operating
Considerations
Operating Costs
First cost or purchase price should not be the only consideration when examining a lighting system. Final cost must be determined by including the system’s performance and operating costs—over both the short- and long-term.
Holophane lighting systems provide the best combination of lighting performance with low owning and operating costs. State-of-the-art optical systems promote energy efficiency and wider spacing between luminaires, which reduces the number of luminaires needed.

Maintenance Ease
Quality luminaires perform better, last longer and require less maintenance. Design features such as interchangeable parts, a quick disconnect and a hinged door assembly will simplify repairs and reduce the time required to change out lamps.
Holophane glass optical systems never become discolored or attract dust, reducing cleaning requirements and maintain the desired light level. Low copper aluminum alloys used for fixture housings are corrosion-resistant, which makes the luminaires appropriate for parking lots, walkways and other outdoor settings.

Lighting Codes and
Regulations
Energy codes, standards and demand side management (DSM) programs help minimize lighting energy waste and assure that facilities use energy efficient lighting systems. Various utilities and government agencies offer incentives that encourage energy efficient lighting designs.
Federal legislation and some state codes have been enacted to establish minimum lighting code requirements for existing or new facilities.

Lamp Life
Lamp manufacturers generally rate the life of their lamps as the time when at least 50 percent of the lamps within a group remain operational under controlled conditions. The initial and replacement costs of the lamp should be considered when the lighting system is designed.

Efficacy
A system’s efficacy is expressed as lumens per watt
(LPW) for either the lamp alone or the lamp and the ballast combined. For HID and fluorescent sources, the system efficacy combines the lamp efficacy with the additional power losses in the ballast. Ballast losses usually range from 5 to 20 percent of the lamp wattage.

Lumen Maintenance
A system’s efficacy is expressed as lumens per watt
(LPW) for either the lamp alone or the lamp and the ballast combined. For HID and fluorescent sources, the system efficacy combines the lamp efficacy with the additional power losses in the ballast. Ballast losses usually range from 5 to 20 percent of the lamp wattage.

Costs
The cost of a lighting system only begins with the purchase and installation costs. The designer must consider operating costs over the life of the system, which includes energy usage and maintenance