Begin Main Content Area

Efficient Lighting

Want to save money and protect the environment? Whether you are a homeowner or a business manager, efficient lighting could be the answer. Efficient lighting involves two concepts:

  1. Using the appropriate amount of light for a given space
  2. Picking the right lighting option for that space

According to the Rocky Mountain Institute, 25 percent of the energy used in the U.S. powers lighting (4/5 of it to the actual light and the rest to cooling all the heat generated by the bulbs). Up to 90 percent of this emergy can be saved just by making better lighting decisions.

Smart Lighting Ideas

Ask why. Why do you need a particular light source? There are generally three kinds of light: ambient, task and accent. Don't light an entire room to a level where you can read a book or show off your china. Use smaller lights for these purposes that aren't on all the time. The most efficient light is the one that gets the job done with minimal energy usage.

Use daylighting whenever possible. Don't close the curtains then turn on the lights. Sunlight is a free source of lighting. Properly placed windows and skylights can eliminate the need for general lighting during the day. Energy efficient windows provide the added benefit of enhancing your homes heating and cooling systems. And some studies have shown that people perform better under natural lighting than they do under artificial lighting.

Paint walls and ceilings with light colors. A little light can go a long way in a light-colored room. Whites and light colors reflect light better than dark colors. There are even commercially available paints and ceiling tiles that are specifically designed to disperse more light throughout a room.

Wash your bulbs. That layer of dust that's settled on your light bulb isn't just dirty; it is preventing some light from leaving the bulb. Cleaning it periodically will improve the amount of light it emits.

Look at the fixture. When that light in the family room goes out, how many of us simply grab the next incandescent bulb we see and install it. The fixture you install it into may actually worsen its performance. For example, installing a regular incandescent or compact flourescent bulb in some recessed fixtures means that up to 50 percent of the light never leaves the fixture.

Exercise control over your lighting options. Obviously making sure you turn off the light when you leave the room is step one. But other controls are available for your needs. Dimmers reduce the amount of energy the bulb is using and increase its life (Note: most CFLs cannot be used with dimmers). Timers make sure lighting sources that need to be on at times don't stay on. Sensors turn lights on in response to movement, body heat or lighting levels.

Buying Bulbs

Lumens, not watts. You're probably used to thinking of bulbs in watts (a 100 watt incandescent being a popular example). However, all this tells you is the energy the bulb will use, not the light it will give off. That 100 watt incandescent bulb only use 10 percent of the energy that goes in to produce light. The other 90 percent is heat, which can impact your electric bill. Lumens is the measure of how much light a bulb puts out. For example, a 100 watt incandescent and a 27 watt compact fluorescent both produce the same amount of lumens.

Look at the life cycle cost. Yeah, that one compact fluorescent light bulb is going to cost you between $6 and $10, while an incandescent may only cost 75 cents. So the incandescent is cheaper right? Well only if you discount the fact that the CFL will last ten times as long (meaning you need to buy ten incandescents) and will use one-quarter to one-third the energy. According to the Rocky Mountain Institute, the life cycle cost of a compact fluorescent light bulb is half that of an incandescent.

Size matters. Most light fixtures in your home or office were designed for a specific type of bulb. If you're going to switch, measure the bulb first. Some compact fluorescents are longer than their incandescent equivalent which can lead to a great deal of frustration when you try installing your new $10 bulb in a globe that is too small.

Compact Fluorescents

A compact fluorescent lighting system has two components: the bulb and the ballast. The ballast starts the bulb and maintains its operation. The bulb - just as it sounds - is a small-diameter fluorescent, folded for compactness. The compact size of these bulbs allows them to screw into common electrical sockets, making them an ideal replacement for incandescent bulbs.

Why use compact fluorescent bulbs?

Energy Savings

A standard incandescent light is very inefficient because much of the energy it uses is turned into heat instead of light. A compact fluorescent bulb turns more of its energy into light and less into heat. In fact it uses 75 percent less energy than standard incandescent bulbs. A 15-watt compact fluorescent system can supply the same amount of light as a 60-watt incandescent bulb. The reduced energy consumption prevents pollution from electricity generation.

Quality of Light

The quality of light produced by a compact fluorescent is comparable to that of the incandescent bulb. There is no flicker or hum with a compact fluorescent -- characteristics that are generally associated with fluorescent lights.


Compact fluorescent bulbs last 10 times longer than standard incandescent bulbs. Compact fluorescents are rated for 10,000 hours and incandescents are typically rated for 1,000 hours. If you have a bulb that is on eight hours a day, a compact fluorescent will last 3.4 years. If a standard incandescent were used, it would have to be replaced 10 times.


Compact fluorescents can replace the two common types of incandescent bulbs: the pear-shaped bulb and the flood bulb. The following provides examples of wattage ratings for comparable light output:

Incandescent: 40w 60w 75w 100w
Fluorescent: 9w 15w 20w 27w


A compact fluorescent system usually costs between $7 and $28, depending on the large range of features. (See the "Specifications" section.) The relatively high initial cost is recovered after only one year of operation (when used eight hours every day), and further savings are achieved over its lifetime. The following comparison shows the total cost (energy and bulb) of operating an incandescent and compact fluorescent bulb for eight hours a day for 3.5 years.

Additional Savings for Commercial and Institutional Buildings

Compact fluorescents generate 75 percent less heat than standard incandescent bulbs. This will greatly reduce the cooling load in buildings with air conditioners. Also, the 10-fold increase in bulb life significantly reduces labor costs for bulb replacement.


Magnetic or Electronic Ballast

Magnetic core and coil ballasts are the least expensive options, but they have some disadvantages. There will be a slight delay before the bulb strikes, especially in lower than normal room temperatures. Magnetic ballasts also are heavier, so they could be inappropriate for floor lamps because they would make the lamp top-heavy. Electronic ballasts represent the latest in lighting technology. They are lightweight and allow the bulbs to light almost instantaneously. They may cost more, but since they use less energy, the higher cost is more than recovered during their lifetime.

Reflectors, Lenses and Other Enhancements

Compact fluorescents can come equipped with reflectors to control the beam spread and/or with lens covers to diffuse the light. They also are available in a variety of colors. The growing popularity of the compact fluorescent has led to an increasing variety of fixtures designed specifically for them. As the market demands adaptation for a variety of existing fixture types, new configurations of bulbs and ballasts are being introduced. New products include shorter bulbs and ballasts that are shorter, narrower or offset to the side of the bulb. Modular or Integrated Modular units have two separate components: bulbs and ballast/adapters. Bulbs typically last 9,000 operating hours (approximately 3.4 years if burned 8 hours per day), while the ballast can last 10 years. Modular units save money over time because bulbs can be purchased at one-third the cost of the entire system. Adapters also can be hard-wired in place thereby preventing the possibility of switching back to more costly incandescent. Integrated units have a combined bulb and ballast.

Some Words of Warning

  • Dimming Circuits
    The compact fluorescents available today cannot be operated safely on standard dimming circuits. The dimmer must be replaced by a standard switch before compact fluorescents may be installed. Recently, dimmable compact fluorescent bulbs have been introduced on the market. However, they require special dimming controls.
  • Different Shape
    Some compact fluorescent bulbs may be longer than traditional incandescents because they need a ballast and because of the unusual lamp shape (long, folded tubes). Be sure to measure the fixture (length, width and depth) before you buy a compact fluorescent.
  • Operation Outdoors or in Cold Temperatures
    While compact fluorescents function efficiently in an enclosed heated space, most are not designed to operate outdoors or in cold indoor temperatures. Typically, electronically ballasted compact fluorescents work in colder temperatures.
  • Delayed Startup
    Even under ideal operating conditions, bulbs with magnetic ballasts may take a second or two to turn on, and they might flicker initially. Electronic ballasted units will come on instantly, with no flicker. Also, compact fluorescent bulbs may require two to three minutes to achieve full light output.

Where to Buy Compact Fluorescents

All major light bulb manufacturers have a line of compact fluorescents. Their availability has greatly improved over the last few years. Compact fluorescents are available at home improvement, grocery and department stores as well as at commercial light bulb supply outlets.

Exit Signs

The exit signs throughout your building are likely lit with an incandescent lightbulb. If you've read the information on compact fluorescents, you know about the dollar and energy savings. With exit signs there is the additional concern for safety. The longer the bulb lasts, the more you can be sure people can leave the building in case of an emergency. If you have to change your light bulb five times a year (or more) as you do with an incandescent, you increase the risk of a bulb being out at a critical moment. Read below to find some better options.

Easy Advice: Look for the EnergyStar label!

EnergyStar labeled exit signs will save energy, but they also will last longer than incandescent fixtures. If you buy an EnergyStar exit sign, you will likely see most of the features described below.

LED Exit Signs

Light-emitting diode (LED) exit signs are the best all around option. They use as little as 1 watt (or 9 kilowatt-hours per year). They can last ten years or more. And they meet visibility requirements and building codes.

The cost for LED exit signs starts at about $80, but because the unit won't need to be replaced for ten years and uses less energy, the payback is typically two years or less.

There are two options for replacing existing exit signs. One is to simply replace the whole unit while the other is to buy a kit that will allow you to retrofit your existing sign.

Compact Fluorescent Exit Signs

There are also exit signs that allow you to replace the two incandescent bulbs with two five watt compact fluorescents. These last about two years so, while they are cheaper than LEDs, they won't last as long and use more energy.

Fluorescent Tubes

The most common fluorescent tubes used today are 40-watt, 4-foot lamps and 75-watt, 8-foot lamps known as T-12 bulbs. The "12" refers to the lamps diameter in eighths

Although fluorescent lamps are generally energy efficient, there are new, even more efficient lamps that use better electrodes and coatings than do older fluorescent lamps. They produce about the same lumen output with substantially lower wattage.

Common 40-watt and 75-watt lamps can be replaced with energy-saving T-8 lamps of 34 watts and 60 watts, respectively. Energy-saving lamps for less-common fluorescent fixtures are also available.

If you need to replace the ballasts in your fluorescent fixtures, consider using one of the improved varieties. These fluorescent ballasts, called improved electromagnetic ballasts and electronic ballasts, raise the efficiency of the fixture 12 percent to 30 percent.

The new electromagnetic ballasts reduce ballast losses, fixture temperature, and system wattage. Because they operate at cooler temperatures, they last longer than standard electromagnetic ballasts.

Electronic ballasts operate at a very high frequency that eliminates flickering and noise. They are even more efficient than improved electromagnetic ballasts. Some electronic ballasts even allow you to operate the fluorescent lamp on a dimmer switch, which usually is not recommended with most fluorescents.

All fluorescent lights contain small amounts of mercury. Because of these hazardous materials, you should not toss burned-out lamps into the trash. Find out if there is a recycling program for them in your community --they are becoming more common-- or dispose of them with other household hazardous wastes such as batteries, solvents, and paints at your community's designated drop-off point or during a designated day when you can put such materials with your curbside trash pickup.

Outdoor Lighting

Can outdoor lighting have negative impacts?

Large-scale outdoor electric lighting is a modern phenomenon that began in an era of abundant and seemingly endless energy resources. This abundance of resources led to the development of inefficient outdoor lighting designs. Problems caused by inefficient outdoor lighting are:

  • Energy Waste and Pollution - Today, we recognize that our energy resources are limited and pollution is an increasing problem. Inefficient outdoor lighting contributes to excessive consumption of fossil and nuclear fuels. This increased consumption causes a corresponding increase in air, water and soil pollution due to processes such as mining, drilling, refining, accidents during transport, combustion (fossil fuels) and waste disposal.
  • Reduced Visibility - Facilities that are too brightly lit (overlighting) may prevent passing motorists from seeing vehicles or pedestrians exiting the facility. Glare from poorly shielded or misaimed fixtures also contributes to this problem. In addition, motorists exiting the facility suffer a temporary reduction in visual acuity.
  • Light Trespass - Light spills into areas where it is not needed or wanted, creating neighbor relation problems.
  • Higher Utility Bills - Inefficient outdoor lighting uses excessive energy to achieve the desired level of illumination; and often, illumination levels are higher than needed. A fixture using an efficient 180-watt low pressure sodium lamp will consume approximately $70 of electricity per year at $0.08 per kilowatt hour. An inefficient 700- watt mercury vapor lamp would consume $250 of electricity. Both lamps produce roughly the same amount of light. This means higher electrical usage and higher utility bills for the lighting consumer. Not only does efficient lighting protect the environment and conserve our energy resources, it saves the consumer money!

Efficient Outdoor Lighting

The efficiency of outdoor lighting is determined by the control of light dispersement, lamp efficiency and the appropriateness of the level of illumination. The following list describes the characteristics of efficient light disbursement and control:

Fixtures for parking area, walkway and street lighting should direct all of their light to the ground; Fixtures should illuminate signs and billboards from above rather than from below; Architectural lighting should illuminate only the intended target. Spill lighting is avoided; In all cases, lighting is shielded to prevent both uplighting and directing light over great horizontal distances. Full cutoff fixtures that emit no light above the horizontal plane should be used whenever practical; and Lights should automatically be turned off or dimmed during off hours.

The most efficient lamps (bulbs) for outdoor lighting are:

  • Low pressure sodium: The most efficient lamp commonly used for outdoor lighting. An excellent choice for any application where color rendering is not important. A good choice for residential security lighting if it is a full cutoff fixture;
  • High pressure sodium: Second in efficiency to low pressure sodium. Can give moderate to excellent color rendition, depending on specific lamp design. A good choice for residential security lighting if it is a full cutoff fixture; and Metal Halide: Though less energy efficient than low or high pressure sodium, this is still an efficient fixture. Best used in public and commercial parking areas if color rendering is paramount.

The following items or practices should be avoided:

  • Mercury vapor lamps
  • Incandescent and quartz halogen lamps (except where used with motion detector)
  • Fixtures that direct light upwards or over large distances horizontally (poor or no shielding);
  • Overlighting.

Preserve The Night Sky

Prior to widespread use of electric lighting, the night sky was a stunning view with several thousand stars visible on a clear, moonless night. With the growth of electric lighting and urban sprawl, the view of the night sky gradually retreated to rural areas. Now, even the once dark skies of rural areas are threatened by urban sprawl. Within a few decades, a star-filled night sky may be a distant memory. The use of efficient outdoor lighting can greatly curb this threat since overlighting and uplighting are avoided.

For more information, contact:

S. Stubbe
Pennsylvania Outdoor Lighting Council
141 Azalea Circle
Limerick, PA 19468

Illuminating Engineering Society of North America
120 Wall St.
New York, NY 10005-4001

International Dark-Sky Association
3225 N. First Sky Ave.
Tucson, AZ 85719

Hire A Lighting Professional

Commercial lighting projects usually are of sufficient scale to justify retaining a lighting professional for design. A good place to begin the search for a qualified professional is the Illuminating Engineering Society of North America (IESNA), a major trade organization for lighting professionals. As a lighting consumer, you should stress to the professional that you want the following items considered in the lighting design:

Use the most efficient lamp suitable

  • Use full cutoff fixtures whenever practicable (beware of semicutoff and noncutoff);
  • Be considerate of neighbors-avoid light trespass and blinding glare; and
  • Protect the visibility of the night sky, avoid uplighting.

A qualified lighting professional will be able to incorporate these criteria into your design. The use of efficient lighting will protect the environment, conserve energy resources, make neighbors happy and protect your wallet!

Traffic Signals

Traffic signals in the U.S. use over 3 billion kilowatt-hours per year. Potential savings from using efficient traffic signals totals about $250 million per year. These efficient alternatives use light-emitting diodes instead of traditional incandescent lamps.

Easy Advice: Look for the EnergyStar label!

EnergyStar labeled traffic signals are energy efficient and will save you money. Look for the EnergyStar label next time you purchase traffic signals.

The Basics

Traffic signals have three colors: red, amber (or yellow) and green. Because of the needed intensity for each light, red bulbs actually use more energy than amber or green.

The most commonly available LED bulb is red, followed by green. Amber is available in LED bulbs but is relatively new to the market.

The most important bulb to replace is the red because (while it is on as long as green) it uses the most energy. While amber is not "on" as much as red and green, to fully take advantage of some of the benefits of LED traffic signals, amber will be necessary. Amber bulbs are also being developed for use in other lit highway signs. The Pennsylvania Department of Transportation maintains specifications for traffic lights.

Why Use LED Signals?

  • Less Cost
    As with many lighting products, while you pay a premium up front, the life cycle savings tilt heavily in favor of LED traffic signals. Because they use 90 percent of the energy, they also have 90 percent of the energy cost.
  • Less Energy Usage
    LED trafic signals use 90 percent less electricity to run. Because the signals are always on, this is particularly during periods of high energy demand throughout the year,
  • Less Maintenance
    A common practice in many municipalities today is to change out traffic lightbulbs annually, not because they have gone out, but just in case they do. LED traffic signals last 5-7 years (many with warranties for that length of time) meaning a reduced schedule for replacement and less opportunity for outages that may disrupt traffic or cause an accident.
  • Safer Roads
    Anyone who has seen an LED traffic signal was probably struck by how bright the light is, a big safety advantage. Because of the small amount of electricity needed for these signals, municipalities can also put them in rural areas and couple them with a backup battery (and possibly a solar panel) to ensure that if the power goes out, the traffic lights stay on.

Case Study: City of Philadelphia

As a result of the successful pilot, in April 1997, the City of Philadelphia Energy Office and the Streets Department began a two-year, $3 million replacement effort to upgrade 28,000 traffic signal lights with energy-efficient LED lamps. Energy savings from this LED project totaled $270,000 in 1998. During fiscal year 2000, the first full year of city-wide red LED signal operations, the estimated annual savings in energy and maintenance costs will be more than $1 million.