LIGHTING UP SAVINGS
Lighting is an essential part of your business and brings many benefits, from boosting employee performance to encouraging sales. However, inefficient lighting can also rob your business of much needed working capital by unnecessarily increasing your energy bills. By now, most people have heard that they can take easy steps like swapping out their incandescent bulbs for more efficient compact fluorescent lamps (CFLs). However, businesses often must take more involved steps to achieve significant energy savings. By accounting for 20-50% of a business’ electricity consumption, lighting ranks second in its contribution to the energy bills for most businesses behind only the heating, ventilation and air conditioning systems, but can yield the highest return on investment for major upgrades due to continually improving equipment.
High-performing and energy-saving lighting systems require a combination of proper technology selection and effective design. The questions below will help you to identify opportunities for cost effectively retrofitting your lighting system. The choice of whether to perform the upgrades yourself or to contact a lighting professional will depend on the level of skill and technical expertise of your facility staff.
- How do I know if my lighting system needs to be retrofitted?
- What are considered “inefficient” technologies and what are some options for replacing them?
- What simple upgrades are most commonly used to save money and energy?
- What automated controls can I use to improve my lighting system efficiency?
- What should I consider in designing an efficient lighting system?
- When should I consider having computer models of my lighting system developed?
- What incentives and rebates are available to help reduce the costs of my lighting retrofit?
- A commercial energy audit, offered by many utilities, can evaluate your lighting system and provide recommendations, upfront costs and projected savings associated with a lighting retrofit. Or, you can do an initial audit yourself as outlined below.
- Grab a notebook, ruler and ladder and take a walk around your facility. It is time to assess the technologies you are currently using.
- Record the number of standard “A” bulbs (this is what you commonly picture as a light bulb) or halogen bulbs installed in task lighting, wall sconces, recessed can fixtures, lamps, suspended fixtures, accent or track lighting, exit signs, or other interior or exterior lighting. Standard “A” bulbs and halogen lamps use incandescent lighting technology that provides a very poor level of light per amount of energy consumed (lumens/watt) and should be replaced.
- If you have overhead lighting fixtures with long tube lights, measure the diameter of the tube. If the tube is 1.5 inches in diameter, you are operating inefficient T12 fluorescent lamps that should be upgraded to either T8s (1-inch diameter) or T5s (5/8-inch diameter) tubes.
- Observe your overhead lights. If they hum or flicker, they are likely operating on magnetic ballasts. The magnetic ballast technology was created in 1939 and is still in use today due to its low initial costs, but new electronic ballasts use 30% less energy and significantly reduce flickering and humming.
- Check your garages, warehouses, areas with high ceilings and security lighting for high-intensity discharge (HID) systems. Many older installations use extremely inefficient mercury vapor lamps. Mercury vapor lamps should be upgraded to metal halide or high-pressure sodium lamps.
- In addition to surveying your facility or talking with your maintenance staff to identify the technologies in use , you can survey the occupants of your facility to gather information on their impressions of the lighting levels. You may end up with valuable information related to complaints of glare or eyestrain that can help guide your lighting retrofit in ways such as identifying areas of overlighting.
- While many factors go into optimal lighting system design and technology selection, including life cycle costs, intended use, and color temperature and rendering, an easy measure of lighting system efficiency is the efficacy of the system, also known as the ratio of the amount of light produced to energy consumed measured in lumens per watt. More efficient systems generate greater lumens per watt yielding a higher efficacy. The Department of Energy lists efficacy ranges for standard lighting technologies as detailed in the descriptions below.
- Incandescent lighting technology such as standard “A” bulbs and halogen lamps are used throughout many facilities in places such as recessed can fixtures, wall sconces, suspended fixtures, lamps, task lighting, accent lighting, track lighting, exit signs and exterior lighting. Standard “A” bulbs are very inefficient, converting up to 90% of their incoming energy to heat instead of light with a efficacy range of 10-17 lumens/watt. Halogen lamps have only slightly higher efficacies of 12-22 lumens/watt.
- If your incandescent lighting system is used for more than two hours per day, you should replace it with a fluorescent lighting system consisting of either a compact fluorescent lamp (CFL) or straight tube fluorescent lamp (T8 or T5) depending on the application. CFLs have efficacies of 50-70 lumens/watt while straight tube fluorescents range from 30-110 lumens/watt.
- For high-intensity discharge lighting systems (common outdoors and in parking garages), mercury vapor lamps are often used in older fixtures. Mercury vapor lamps are quite inefficient, generating only 25-60 lumens/watt. Consider replacing these with metal halide lamps that have an efficacy of 70-115 lumens/watt or high-pressure sodium lamps with an efficacy of 50-140 lumens/watt.
- Light-emitting diode (LED) and induction lamps are newer technologies that may be appropriate for your upgrade depending on the proposed application and their costs. LEDs are highly efficient, durable and have long lifetimes but have largely been restricted so far to specialty uses such as accent lighting, traffic signals, exit signs, LCD monitor backlighting, brake lights and strings of holiday lights. Induction lamps have high installed costs but have very long lifetimes (up to 100,000 hours) and may be good choices if relamping or maintenance are difficult, hazardous or costly.
- A more detailed discussion of each lighting technology is available in the lighting chapter of ENERGY STAR®’s building upgrade manual.
- Replacing incandescent lamps with compact fluorescent lamps.
- Replacing incandescent lighting systems with fluorescent lighting systems.
- Replace T12 fluorescent lamps with magnetic ballasts with T8, or T5 fluorescent lamps with electronic ballasts, and
- Replace high-intensity discharge mercury vapor lamps with metal halide or high pressure sodium vapor lamps.
- In identifying controls to implement, try to maximize lighting flexibility through the ability to manually override settings while eliminating light usage automatically where possible.
- Bi-level switching can be used to group sets of fixtures or lamps, enabling occupants of a room to only turn on some of the lights, if desired.
- Dimmers for incandescent and fluorescent systems can be used to control the amount of light output and to save energy. Some dimmers allow occupants to manually adjust lighting levels while daylight dimmers automatically reduce room light based on the availability of natural light.
- Occupancy sensors control lighting by detecting the motion of room occupants. Depending on the space, these sensors can save from 20% to more than 50% of the lighting energy used. Occupancy sensors automatically turn lights off when no one is present and can be set to turn lights back on either when a person enters a room or as they approach, depending on placement of the sensor.
- Daylight sensors (photocells) are used to turn exterior lights on and off based on the presence of daylight. They are more effective than timers because they adjust to changing daylight levels throughout the year and do not require manual resetting of timer schedules as seasons change.
- Begin by identify the proper quality and quantity of light for the area. Illumination is measured in footcandles (fc) with one footcandle equaling one lumen distributed over a one square foot area. You can measure footcandles at your facility with a standard portable light meter. Use the guidelines below from ENERGY STAR to check for proper illumination levels in your current building. Give your system at least 30 minutes to warm up, conduct the survey after dark if possible to eliminate daylighting impacts, and be sure to place the light meter at the proper height and to measure both directly under fixtures and between fixtures.
|Space Type||Horizontal Surface (FC)||Vertical Surface (FC)|
|Open Plan Offices||30-50||5|
|Hotel Guest Rooms||10||-|
|Retail Merchandise Displays||50||10|
|Open Parking Lots - Enhanced Security||.5||.25|
- You may want to contract with a certified lighting designer or a certified lighting professional. Find one in your area by visiting the registries at the International Association of Lighting Designers or the National Council on Qualifications for the Lighting Professions.
- More light is not always better, as light quality can often be as important as light quantity. By combining efficient lighting technologies with fixtures that use reflectors or other technologies to better distribute light, you may be able to delamp some existing fixtures and still maintain adequate light in your workspace. For example, a fixture with 4 T12s and a magnetic ballast may be able to be replaced with a fixture with 2 T8s, an electronic ballast, and a specular reflector and lens. The more efficient lamps and fixtures along with the 50% delamping could reduce the energy consumption of the fixture by more than 70% while maintaining the same level of illumination.
- Task lights can be used to effectively provide on-demand light when needed while allowing ambient light levels to be reduced.
- If your fixture is mounted on the ceiling or wall and will be on for more than two hours per day, you should install fluorescent light fixtures.
- Use compact fluorescent lamps (CFLs) in portable fixtures that will be used more than two hours per day.
- Purchase ENERGY STAR qualified lighting technologies and fixtures.
- Use occupancy sensors to automatically turn off lights when rooms are empty.
- Use dimmers to allow occupants to manually reduce lighting levels.
- Use daylight dimmers to automatically adjust lighting levels based on the amount of natural light present.
- Consider painting walls a lighter color to reduce ambient lighting requirements.
- One footcandle of illumination is generally adequate for outdoor applications.
- Security lighting does not necessarily have to be bright to be effective.
- Choose fluorescent or efficient high-intensity discharge lamps, such as metal halide or high-pressure sodium, over incandescent or mercury vapor lamps.
- Use reflectors, deflectors and covers to more effectively distribute outdoor light and to minimize light pollution.
- Use daylight sensors (photocells) to turn outdoor lighting on and off.
- For more in depth discussion of each lighting technology and the ENERGY STAR recommendations for upgrading your building’s lighting system, read the lighting chapter of ENERGY STAR’s building upgrade manual.
Computer models can be used to optimize your lighting system if you are building new construction or performing a major retrofit. In these circumstances, you are less bound by the current location of lighting fixtures and have more flexibility in designing the optimal system for your facility. Lighting modeling can help you maximize daylighting and properly coordinate selection of lighting technologies and fixtures, fixture placement and room finishes to ensure the proper lighting levels in your workspaces.
Use Recharge Colorado’s Energy Action Planner to identify incentive and rebate opportunities that match your needs for a lighting retrofit.