Lighting in Small Businesses 1

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1 Fact Sheet EES-69 Lighting in Small Businesses 1 Adapted by Roy Johannesen 2 Lighting is essential to retailing. Studies have shown that lighting affects the marketability of products ranging from produce to jewelry. In addition, good lighting improves employee comfort and productivity. However, lighting is usually the second largest energy user in commercial facilities, and in some retail stores may even be the largest. In addition, heat generated by lighting constitutes a significant portion of the heat load that must be removed by the air conditioning system. Thus, it is important to use lighting wisely and efficiently. LIGHTING CHARACTERISTICS Good lighting is determined by the light source s efficiency, color rendition, color temperature and lamp life. Efficiency is a measure of how much visible light is produced (lumens) per unit of electrical power (watts). The more efficient lighting sources give off more light for the same amount of power. In addition to being efficient, a lighting source should also render color in an acceptable manner. Color rendition refers to an object s perceived color under a light source compared to the perceived color of that object when illuminated by natural sunlight. Color temperature is different than color rendition and describes an aesthetic quality rather than color accuracy. Color temperature is typically described on the label in phrases like "deluxe cool white" or "warm white." Low color temperatures produce warm (red) tones; high color temperatures produce cool (blue) tones. Lamp life can vary greatly and is an important factor in life-cycle costing of various lamp types. Incandescents average as little as 750 hours while fluorescents and other high efficiency lamps last 20,000 or more hours. TYPES OF LIGHTING Several lighting sources are available for retail use including incandescent, fluorescent and high-intensity discharge (HID). Each type has characteristics that make is especially suited to different needs in a retail establishment. Incandescent Lighting Incandescent lamps use the most energy per unit of light produced. Ninety percent of the energy consumed by an incandescent lamp is given off as heat rather than visible light. Incandescents are not the least expensive lamp to purchase because they have a relatively short lifetime. Every other variety of lamp outlasts standard 1. This document is Fact Sheet EES-69, Florida Energy Extension Service. It was adapted for Florida, with permission, from a document originally created by the Texas Energy Extension Service. For more information, contact your county Cooperative Extension Service Office. 2. Roy Johannesen, Energy Extension Specialist, Energy Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / Christine Taylor Stephens, Dean

2 Lighting in Small Businesses Page 2 out. Now, models like the "warm white" and the "deluxe cool white" have much better color rendition. That makes them acceptable in display cases, showrooms and other areas where good color rendition is important. Other innovations in fluorescent lamp designs have made them easier to use. Some new models have built-in ballasts, so they can fit into standard incandescent sockets. Others have been specially designed to fit in places too small for standard-sized fluorescent fixtures. These compact fluorescents come in several forms: Figure 1. Incandescents vs. fluorescents. incandescents by an average of 10 to 20 times. A "cheaper" lamp that must be replaced ten times as often as a more "expensive" lamp is not necessarily a bargain! Despite their drawbacks, incandescents are sometimes useful in display cases or in providing accent or mood lighting in restaurants. They are also appropriate in closets and other locations where they are turned on infrequently and for brief periods of time. "Circline" is the generic name for a lamp produced by several lighting manufacturers. The fluorescent tube is circular and can fit into many standard incandescent sockets. It produces as much light as a 100-watt incandescent bulb for only 44 watts. Compact "U-tubes" (named for their shape), or "PL" lamps are designed to fit into many places too small for ordinary fluorescent lamps and fixtures. Many models have built-in ballasts and can be used in Fluorescent Lighting Fluorescent lamps convert electric power to visible light by using an electric charge to "excite" gaseous atoms. These atoms emit ultraviolet radiation that is absorbed by a phosphor coating on the walls of the fluorescent tube. The phosphor coating produces the visible light. These lamps require a ballast, a small transformer that regulates the voltage and current flow necessary to initiate and sustain the charge. Fluorescent lamps convert electricity to visible light up to three to four times more efficiently than incandescent lamps and last up to 25 times longer. Figure 1 demonstrates the advantages of fluorescents compared to incandescents. Recent improvements in fluorescent lamp designs have made them acceptable for a wider range of uses. The lighting industry has produced several lamp models that correct the poor color rendition characteristics of some older lamps. Older model fluorescents could make colors look flat and washed Figure 2. A PL fluorescent light.

3 Lighting in Small Businesses Page 3 incandescent fixtures. They are excellent in places like exit lights, track lights and recessed fixtures (see Figure 2). Other compact fluorescents have the look and physical size of incandescents. Everything they need is already built-in: ballast, screw base, fluorescent lamp and translucent globe. They fit into virtually any standard incandescent fixture and produce more light than a 60-watt incandescent lamp for only 17 to 20 watts. The initial cost of these new fluorescents is relatively high ($8 to $20), but they last about 10,000 hours and use two-thirds less energy than incandescents. High Intensity Discharge Lighting High intensity discharge (HID) lamps are another alternative to incandescents and fluorescents. There are four types of HIDs: metal halide, high and low pressure sodium, and mercury vapor. Low pressure sodium lamps are rarely used in the United States because their color rendition is very poor. They are, however, the most efficient of the HIDs and while their color rendition is very poor, it is very effective in areas requiring security, such as parking lots, garages, and high theft areas. Other HIDs are better in this regard but are often still considerably distorted from "natural" light. Also, HID lamps have a delayed initial and restrike time--that is, they don t come on instantly. This time delay ranges from 3 to 15 minutes, depending on the type of HID lamp. That can make HIDs unacceptable for areas when an instant start is necessary. Metal halide has excellent color rendition, but it is the slowest to restart after a power shut-off. Table 1 compares the lumens per watt and the life expectancies of various types of lamps. As with miles per gallons (mpg) for cars, the lumens per watt (lpw) of a particular model lamp should be an important factor in your purchasing decision. LIGHTING LEVELS The traditional measurement unit for lighting is the footcandle (FC), which is the amount of light emitted by a candle from a distance of one foot. The chief source for recommended lighting levels is the Illuminating Engineering Society of North America s (IES) Handbook, Reference Volume, 1981 (see Table 2). The lighting section in ASHRAE 90, essentially authored by IES, is also a good reference. Lamp manufacturers also have information available on lighting. Finally, many electric utility companies have lighting consultants, and some even offer financial incentives for you to reduce the lighting load in your building. Many facilities were designed with more light than necessary for the area s tasks. To determine if a facility is over-lighted, first check the existing light levels with a light meter, which can be purchased at electrical supply houses for about $60 and up. Place the light meter on the work surface and record the light level (in footcandles) indicated by the needle. You may want to take three or four readings around the area and average them. Compare your reading with the recommended task light level shown in Table 2. If the area gets more light than necessary, remove unneeded lamps. DELAMPING If an area is overlighted, removing lamps (and ballasts in the case of fluorescent tubes and HID lamps) is a good solution. Care should be taken in delamping, however, to assure that the remaining light is adequate and evenly distributed. Uneven light patterns or insufficient light can cause eye strain and hamper productivity. For example, if you determine that an area lit by a four-lamp fixture has twice the amount of light necessary, you can remove two of the lamps powered by the same ballast for the reduction you need. Make sure to also disconnect the ballast, which will draw an average of 16 watts even without the lamps. Sometimes removing several lamps creates shadowy or uneven lighting. And other times it won t be possible to remove the number of fluorescent lamps for the needed lighting reduction. For example, you can t lower the light level of a four-lamp fluorescent fixture 25 percent by removing one lamp. If you remove only one lamp, the remaining lamp powered by the same ballast won t work and you may damage the ballast. After delamping, be sure to re-check the available light at the work surface with a light meter. Sometimes, a desk lamp or other supplemental "task lighting" may be needed. This can significantly lower total energy cost without sacrificing light intensity (Figure 3).

4 Lighting in Small Businesses Page 4 Table 1. Light output and rated life of selected lamp types. Type of Lamp 1 Commonly Used Wattage Sizes Initial Lumens Per Watt 2 Rated Life 3 (hours) INCANDESCENT Standard ,000 Standard Standard ,000 Quartz (Halogen) ,000 Quartz (Halogen) 1, ,000 MERCURY VAPOR Self-Ballasted ,000 Standard ,000+ Standard ,000+ FLUORESCENT Compact ,000 Circle Tube ,000 Energy Efficient (4 cool white) ,000 Standard (4 cool white) ,000+ METAL HALIDE Standard ,000 Hi-Output ,000 Hi-Output 1, ,000 HIGH PRESSURE SODIUM Standard 1, ,000+ LOW PRESSURE SODIUM Standard 4 1, , Lamps (except low pressure sodium) are clear or "white" models selected from G.E. product catalogues as representative of classes. Includes ballast factors of 0.15 HID and 0.2 fluorescent. Rated life is the point at which 1/2 of a test group of lamps has burned out. Low pressure sodium lamps are not manufactured in the United States.

5 Lighting in Small Businesses Page 5 RELAMPING The question of replacing lamps as they burn out versus group relamping persists. Relamping an entire area requires greater expense, and many people are reluctant to discard lamps that are still functioning. On the other hand, if all the lamps in the area are near the end of their rated life expectancy, group relamping may be cost effective for two reasons. First, as lamps get older, light output drops off significantly while the amount of energy consumed remains the same. Second, relamping an area all at once reduces labor costs. Industry studies indicate that half an hour is needed to change a single lamp, while a crew assembled to relamp an entire area can finish the job in an average of about 3 minutes per lamp. Energy-efficient ballasts last at least twice as long as standard "core and coil" ballasts and use half the energy (8 watts versus 16). Using energy efficient lamps with standard ballasts may reduce the useful life of the ballast and lamp slightly, but economics alone will seldom justify group replacement of ballasts. A general rule is to use only energy-efficient models (about $17 to $20) when replacing failed ballasts. In new installations or major renovations, you should consider one of the new three-lamp systems. One ballast controls three lamps instead of two, saving on both the capital cost and energy cost. LIGHTING QUALITY Here are some key points to consider on the issue of light quality. Brightness Brightness is determined by the relative amount of light available at the work surface in relation to the level of illumination in the field of view. The eyes function most comfortably and efficiently when the brightness relationships (contrast) are not excessive. The light at the desk surface should not be more than three times the level of light immediately around the desk. Table 2. Suggested lighting levels. Area Approximate Light Level (footcandles) Offices 75 Conference Rooms Auditoriums Kitchens 50 (avg.) Cafeterias Warehouses/Workshops Reception Areas Drafting Rooms Accounting Offices Corridors/Restrooms Bank Lobby Writing Areas General Areas Teller Stations Doctor s Treatment Areas 200 Storage Rooms 5-50 Stores (general) Stores (sales displays) (Source: 1981 Illuminating Engineering Society (IES) Handbook) Glare Avoid conditions that create glare. The position of the light source in relation to both the viewed surface and the eye is critical. For example, light in front of a desk that strikes the surface at the same angle as it is reflected into the eye (veiling reflection) can create considerable eye strain. The best ceiling lighting comes from either side of the work surface.

6 Lighting in Small Businesses Page 6 Figure 3. Appropriate task lighting. Color Rendition Color rendition, described earlier, is another measure of light quality. Basically, color rendition is a means of comparing the quality of colors as perceived under various artificial lights to that same color viewed under natural sunlight. With the advent of fluorescent and high-intensity discharge lamps, it became obvious that not all lamps provide the same rendition of color. Thus, consumers should consider the task being performed and the importance of natural color rendition before selecting a lamp type. Incandescent lamps are generally the closest to natural sunlight and low pressure sodium lamps give the poorest color rendition. There are new fluorescents on the market that are almost as close to sunlight as the conventional incandescent. Metal halide easily provides the best color rendition among HID lamps. Visual Comfort Visual comfort and ease of seeing are dependent not only on brightness, glare and color rendition, but also on the fixture placement and design, and the amount of contrast within the visual task. OTHER CONSIDERATIONS Turning Lights On and Off The old principle of leaving lights on if the room is unoccupied for no longer than 15 minutes no longer holds true. Manufacturers now recommend that incandescents be turned off anytime you leave the room, and fluorescents be turned off for any period exceeding 2 to 3 minutes. HID lamps, however, should not be turned on and off for periods of less than hour because of the 3 to 15 minute restart time required to get lamps back up to full intensity.

7 Lighting in Small Businesses Page 7 Reminder stickers by the light switch often help. Some companies have run poster contests and other incentive programs to get employees to turn lights off in unoccupied areas. Low-Voltage Lighting Low-voltage incandescents use less voltage than the normal 120 volts most businesses use. A built-in, step-down transformer powers the lamp with as little as 12 volts. Low-voltage incandescents are designed to focus the light beam at the work surface, so you get the light where you need it. A 25-watt low-voltage lamp provides as much light as a standard 75-watt incandescent lamp. Savings can be even greater because low-voltage lamps have a longer life-span than standard incandescents. These low-voltage lamps often require new fixtures, but their total cost is still low enough to make them cost-effective for most businesses. Long-Life Incandescents Although these lamps last longer than standard incandescents they are even less efficient than other incandescents and should be used only in hard-toreach places. Consider a compact fluorescent instead. Elliptical Reflector Lamps If you now use 150-watt flood lamps or standard incandescents in recessed downlights or can fixtures, you re not getting all the light you re paying for. That s because standard lamps disperse their light in such a wide beam that much of it stays in the fixture. An elliptical reflector (ER) helps solve this problem by focusing the light beam outside the fixture, giving you more light at the work surface. In fact, a 75-watt ER often gives you better light than a 150-watt flood lamp. However, a compact fluorescent will be still more efficient, and many of the newer models are designed for recessed fixtures. Timeclocks, Photocells and Sensors A timeclock turns lighting systems on and off at preselected times. Timeclocks are most effective when used to control outdoor signs and decorative lighting. However, dusk and dawn occur at slightly different times each day, so timeclocks may need frequent adjustment. A photocell will make sure your lights are on only when they re needed by sensing the natural light level present. When it determines that the light level is too low, it turns the lights on. When the sun comes up, it turns the lights off. An astronomical timeclock will do the job of both a photocell and a timeclock. It keeps track of the time of year and automatically adjusts for the correct sunrise and sunset times each day. You can also set it to turn lights off at any time during the night just as you would a standard timeclock. Occupancy sensors turn lights on and off when the area is occupied. Some are infrared (heat sensing) technology. others rely on motion detection by radar-like sound waves. CALCULATING LIGHTING SAVINGS The following is a simplified savings formula to help you make lighting decisions. This basic formula determines lighting savings resulting from changes (delamping or installing more efficient lights). watts saved by delamping or installing efficient lamps x x hours per day used days per year used = watt-hours per year saved 1,000 = kilowatt-hours (kwh) per year saved x $ average cost per kwh (in dollars; e.g. $.07) = $ energy dollar savings per year MORE INFORMATION For more information on ways to save energy in your business read the Florida Energy Extension Service factsheets "Reducing Operating Costs Through Improved Energy Efficiency in Your Business--A Checklist" and "Energy Management for Small Businesses." The Florida EES also has factsheets on energy savings in restaurants, and hotels and motels. To receive any of these free factsheets or

8 Lighting in Small Businesses Page 8 for information on other ways to save energy, call your local County Extension Office or write: Florida Energy Extension Service 220 Rolfs Hall University of Florida Gainesville, FL For additional reading, look for the following publications, available from the publisher or your local library or bookstore. "Commercial Energy Management Service Bulletins," San Diego Gas & Electric Company, "Consulting Specifying Engineer" Magazine, September IES Handbook, Reference Volume. Illuminating Engineering Society of North America, Product catalogues: General Electric, Westinghouse, Sylvania, Widelite, Hubbell Supply, ASHRAE 90-A. American Society of Heating, Refrigeration and Air Conditioning Engineers, Lighting Section, 1988.

Westinghouse. Lamps 101

Westinghouse. Lamps 101 Westinghouse Lamps 101 Objectives Explain common lighting terminology to your customers Examine color temperature and explain the Kelvin scale List features and benefits of various lamp types, including: