Indoor Lighting

There are three ways in which lighting energy use can be reduced by building owners: implement a greater degree of control over the use of lighting, use more efficient lighting equipment and apply better lighting system design strategies. Translated into a general guide, the goals statement for a comprehensive lighting energy conservation program should read: turn it off when it isn't needed; use the most efficient, suitable equipment; and provide light only where it is needed.

When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.

Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

Even if you have already retrofitted a lighting system with energy-efficient core-coil ballasts and "watt miser" lamps, you can get further savings with a T8 conversion. The T8 system is, in most cases, the best retrofit method for existing fluorescent lamps. T8 lamps and ballasts are much more efficient than standard lamps and ballasts and their use creates an opportunity for delamping by astute use of reflectors, new lenses and "overdriven" ballasts. Often, existing four-lamp fixtures can be retrofitted with three or even two T8 lamps and ballasts and still maintain the same light output. Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox-mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

Incorporate motion detectors where they make sense. Suppose that you have fixtures with U-shaped fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). If you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three-hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 1/2 years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses.

Employ special strategies to help distribute daylight evenly in multiple-story buildings. Simply enlarging window openings in such structures does not solve the problem. This is because near the ground level, some daylight bounces off the landscaping and streetscaping to balance the light from the sky. In high-rise buildings, you can achieve balance artificially by using reflectors and diffusers built into the glass.

When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

Replace your 10, or 20 watt incandescent lamps in exit signs with 5 watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two lamp 15 watt incandescent sign with two, 5 watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LFD and electroluminescent exit light fixtures can be an effective alternative to CFLs.

Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

Lighting control is perhaps the most important element of any lighting energy conservation program. Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time-based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

Suppose that you have fixtures with U-Shaped 'fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). if you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 ½ years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

Increasing the amount of natural light used in your facilities dramatically lowers your utility bills. The more artificial lighting used, the greater the heat load imposed on the air conditioning system. This is a critical point because artificial lighting and air conditioning consume the largest amount of electrical energy in a typical commercial building.

Lighting control is perhaps the most important element of any lighting energy conservation program Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

Even if you have already retrofitted a lighting system with energy efficient core coil ballasts and "watt miser" lamps, you can get further savings with a conversion to T8 lamps.

Replace your 10-, 15-, or 20-watt incandescent lamps in exit signs with 5- or 7-watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two-lamp 15-watt incandescent sign with two, 5-watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem, thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LED and electroluminescent exit light fixtures can also be an effective alternative to CFLs.

It's a good idea to replace incandescent lamps with compact fluorescent's (CFLs). When doing so, the proper ratio is about 3 1/2% incandescent watts to 1 compact fluorescent watt. There may be an aesthetic problem with replacing incandescent lamps with CFLs in "can" fixtures because these fixtures are not designed for CFLs. The lamps often protrude from the bottom of the fixture and the light distribution from the fixture is poor because its optical characteristics suit an incandescent lamp. Another approach: retrofit with a specially designed reflector and lamp holder that maximizes the optics of the CFL and has a more pleasing appearance.

It's a good idea to replace incandescent lamps with compact fluorescents (CFLs). When doing so, the proper ratio is about 3 to 4 incandescent watts to 1 compact fluorescent watt. There may be an aesthetic problem with replacing incandescent lamps with CFLs in "can" fixtures because these fixtures are not designed for CFLs. The lamps often protrude from the bottom of the fixture, and the light distribution from the fixture is poor because its optical characteristics suit an incandescent lamp. Another approach: retrofit with a specially designed reflector and lamp holder that maximizes the optics of the CFL and has a more pleasing appearance.

Switching from traditional light bulbs (called incandescent) to CFLs is an effective, simple change everyone in America can make right now. Making this change will help to use less electricity at home and prevent greenhouse gas emissions that lead to global climate change. Lighting accounts for close to 20 percent of the average home’s electric bill. ENERGY STAR qualified CFLs use up to 75 percent less energy (electricity) than incandescent light bulbs, last up to 10 times longer, cost little up front, and provide a quick return on investment.

If every home in America replaced just one incandescent light bulb with an ENERGY STAR qualified CFL, in one year it would save enough energy to light more than 3 million homes. That would prevent the release of greenhouse gas emissions equal to that of about 800,000 cars

CFLs contain a very small amount of mercury sealed within the glass tubing — an average of 4 milligrams — about the amount that would cover the tip of a ballpoint pen. By comparison, older thermometers contain about 500 milligrams of mercury — an amount equal to the mercury in 125 CFLs. Mercury is an essential part of CFLs; it allows the bulb to be an efficient light source. No mercury is released when the bulbs are intact (not broken) or in use.

Most makers of light bulbs have reduced mercury in their fluorescent lighting products. Thanks to technology advances and a commitment from members of the National Electrical Manufacturers Association, the average mercury content in CFLs has dropped at least 20 percent in the past year. Some manufacturers have even made further reductions, dropping mercury content to 1.4 — 2.5 milligrams per light bulb.

EPA estimates the U.S. is responsible for the release of 104 metric tons of mercury emissions each year. Most of these emissions come from coal fired electrical power. Mercury released into the air is the main way that mercury gets into water and bio accumulates in fish. (Eating fish contaminated with mercury is the main way for humans to be exposed.)

Most mercury vapor inside fluorescent light bulbs becomes bound to the inside of the light bulb as it is used. EPA estimates that the rest of the mercury within a CFL — about 11 percent — is released into air or water when it is sent to a landfill, assuming the light bulb is broken. Therefore, if all 290 million CFLs sold in 2007 were sent to a landfill (versus recycled, as a worst case) — they would add 0.13 metric tons, or 0.1 percent, to U.S. mercury missions caused by humans.

Electricity use is the main source of mercury emissions in the U.S. CFLs use less electricity than incandescent lights, meaning CFLs reduce the amount of mercury into the environment. As shown in the table below, a 13­watt, 8,000­rated­hour­life CFL (60­watt equivalent; a common light bulb type) will save 376 kWh over its lifetime, thus avoiding 4.5 mg of mercury. If the bulb goes to a landfill, overall emissions savings would drop a little, to 4.2 mg. EPA recommends that CFLs are recycled where possible, to maximize mercury savings

Because CFLs also help to reduce greenhouse gasses, other pollutants associated with electricity production, and landfill waste (because the bulbs last longer), they are clearly the environmental winner when compared to traditional incandescent light bulbs.

CFLs are made of glass and can break if dropped or roughly handled. Be careful when removing the bulb from its packaging, installing it, or replacing it. Always screw and unscrew the light bulb by its base (not the glass), and never forcefully twist the CFL into a light socket. If a CFL breaks in your home, follow the cleanup recommendations below. Used CFLs should be disposed of properly (see below).

EPA recommends that consumers take advantage of available local recycling options for compact fluorescent light bulbs. EPA is working with CFL manufacturers and major U.S. retailers to expand recycling and disposal options. Consumers can contact their local municipal solid waste agency directly, or go to http://www.epa.gov/bulbrecycling or http://www.earth911.org to identify local recycling options.

If your state or local environmental regulatory agency permits you to put used or broken CFLs in the garbage, seal the bulb in two plastic bags and put it into the outside trash, or other protected outside location, for the next normal trash collection. Never send a fluorescent light bulb or any other mercury-containing product to an incinerator.

If your ENERGY STAR qualified CFL product burns out before it should, look at the CFL base to find the manufacturer's name. Visit the manufacturer's web site to find the customer service contact information to inquire about a refund or replacement. Manufacturers producing ENERGY STAR qualified CFLs are required to offer at least a two year limited warranty (covering manufacturer defects) for CFLs used at home. In the future, save your receipts to document the date of purchase.

Because CFLs contain a small amount of mercury, EPA recommends the following cleanup and disposal guidelines:

1. Before cleanup: air out the room:
   • Open a window and leave the room for 15 minutes or more.
   • Shut off the central forcedair heating/air conditioning system, if you have one.
2. CleanUp steps for hard surfaces:
   • Carefully scoop up glass fragments and powder using stiff paper or cardboard and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
   • Use sticky tape, such as duct tape, to pick up any remaining small glass pieces and powder.
   • Wipe the area clean with damp paper towels or disposable wet wipes. Place towels in the glass jar or plastic bag.
   • Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.
3. Cleanup steps for carpeting or rug:
   • Carefully pick up glass fragments and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
   • Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
   • If vacuuming is needed after all visible materials are removed, vacuum the area where the bulb broke.
   • Remove the vacuum bag (or empty and wipe the canister), and put the bag or vacuum debris in a sealed plastic bag.
4. Cleanup steps for clothing, bedding, etc.:
   • If clothing or bedding materials come in direct contact with broken glass or mercury­containing powder from inside the bulb that may stick to the fabric, the clothing or bedding should be thrown away. Do not wash such clothing or bedding because mercury fragments in the clothing may contaminate the machine and/or pollute sewage.
   • You can, however, wash clothing or other materials that have been exposed to the mercury vapor from a broken CFL, such as the clothing you are wearing when you cleaned up the broken CFL, as long as that clothing has not come into direct contact with the materials from the broken bulb.
   • If shoes come into direct contact with broken glass or mercury­containing powder from the bulb, wipe them off with damp paper towels or disposable wet wipes. Place the towels or wipes in a glass jar or plastic bag for disposal.
5. Disposal of cleanup materials:
   • Immediately place all clean­up materials outdoors in a trash container or protected area for the next normal trash pickup.
   • Wash your hands after disposing of the jars or plastic bags containing clean­up materials.
   • Check with your local or state government about disposal requirements in your specific area. Some states do not allow such trash disposal. Instead, they require that broken and unbroken mercury­containing bulbs be taken to a local recycling center.
6. Future cleaning of carpeting or rug: air out the room during and after vacuuming:
   • The next several times you vacuum, shut off the central forced­air heating/air conditioning system and open a window before vacuuming.
   • Keep the central heating/air conditioning system shut off and the window open for at least 15 minutes after vacuuming is completed.

Get rid of mercury lamps inside and outside a building. Their light output reduces over time, and a dim mercury lamp uses as much energy as a brand new one. Replace them with high-pressure sodium or metal halide lamps.

Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to run. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, and if you can tap into utility rebates and other incentives.

Update a system using energy core-coil ballasts and "watt miser" lamps to a T8 system for further savings.

When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.