Most schools are currently using inefficient lighting technologies. You can’t really blame them. When many schools were designed, lighting efficiency was simply not a top priority. So a lot of America’s classrooms are still poorly lit causing eye-strain, fatigue and headaches; all of which may contribute to a measurable drop in student learning.
Health, Safety & Learning
Poor lighting negatively impacts student learning and health. A study by Dr. D.B. Harmon showed that in well-lit schools, visual problems in 160,000 students studied were reduced by 65%, fatigue was reduced by 55%, and infections were decreased by 43%. The study concluded that lighting is a significant contributor to student health and learning.
Lighting is also a safety issue. Well-lit parking lots, hallways and outdoor walkways increase student and public safety. Better lighting results in fewer accidents, deters crime, and decreases liability risk.
Costs, Savings & Environmental Benefits
In a typical school building, lighting accounts for over 30% of electricity usage. Today’s lighting technology offers huge savings opportunities in operating and maintenance costs along with possible improvements in lighting quality and a nice reduction in your carbon footprint. Think about it – for every 1,000 kilowatt hours (kWh) that can be saved, your school will prevent roughly 1,119 pounds of CO2 from being emitted. What better way is there to teach students about environmental responsibility than to demonstrate it to them first-hand on a daily basis? It is in students’ best interests to become well-acquainted with eco-friendly practices and alternatives. Energy Efficiency and the Green movement have become a major focus for businesses and industries who will hire tomorrow’s graduates. Additionally inefficient lights generate a lot of heat which forces a building’s A/C to use more electricity to cool the building. Up to 10% savings in cooling costs may be an additional side-benefit of a lighting retrofit.
Planning Your Lighting Updates
Lighting is regarded as being one of the easiest and cost-effective upgrades to implement. Even so, your lighting needs must be planned carefully to achieve the desired performance and maximize savings. The first thing you need to do is assemble the appropriate operations staff to oversee the entire project. This group will be responsible for obtaining all relevant information and collaborating with all stakeholders regarding the school’s future lighting choices. Initial decisions should invariably include the hiring of a professional energy consultant to perform your school’s comprehensive energy audit.
The data collected from the energy audit forms the basis of the lighting retrofit. The audit assesses in great detail every aspect of a building’s energy performance. Here, vital information is gathered about the existing lighting system and the manner in which it is used. When gathering information about lighting, the consultant will evaluate items such as hours of operation, types of fixtures, quantity of fixtures, lamp types, types of ballasts, daylight availability, area dimensions, room sizes, wall colors, and so on.
After gathering all of the information, the energy audit professional will analyze the data and provide qualified suggestions for changes that can provide significant savings and performance improvements.
Understanding Lighting Technology
To take full advantage of new lighting opportunities, it helps to have a solid grasp of lighting technologies and the principles of how each technology fits into your goals.
Lighting technologies convert electricity into light and heat at various efficiencies. For example, an old incandescent bulb converts 90% of the electricity into heat and only 10% into light. Fluorescent, HIG (high intensity discharge), induction and LED (light emitting diodes) bulbs convert much more electricity into visible light while producing less heat than an incandescent bulb, which means they are more efficient and produce greater savings. Over the past 10 years, there have been significant improvements in lighting efficiency and options. There are significant benefits to a lighting retrofit, even if you did one 3 years ago and a professional will know which technologies will best fit your building’s needs.
Though a professional will be guiding your choices, it is always good to have some basic understanding. To better understand your lighting options, you should have some basic knowledge about how light is measured.
Lux & Lumens
Lumens are measurements of a lamp’s output. A lux is about 1/10 of a lumen. A typical 4 foot T-8 fluorescent lamp produces almost 2,900 lumens while consuming about 30 watts of power. By dividing the lumens by the watts consumed, the lighting yield is approximately 100 lumens per watt. This compares to about 70 lumens per watt for compact fluorescents or 20 lumens per watt for an incandescent bulb. The higher the lumens per watt, the lower the electric bill and the easier it will be to meet the new energy codes that restrict watts per square foot.
When lumens hit a surface (or the light meter) a foot candle level can be measured. One foot candle is one lumen spread across one square foot. Direct lighting is the light that shines directly from the fixture to an object. Indirect lighting reflects off of another surface before hitting the object. Lighting in most situations is a combination of direct and indirect lighting.
Color Rendering Index
There are various shades of white light that vary by their Color Temperature – which in this case, has nothing to do with heat! Higher temperatures are richer in the blue spectrum and lower temperatures are more orange. Lamps with a lower temperature tend to produce a light closer to an incandescent bulb. The CRI is used to compare the color renderings of various bulbs and how close they come to lighting true color: the higher the number, the closer to true color. Normal room lighting should have a CRI of 70 or higher. This chart from the Lighting Fundamentals Handbook will illustrate the difference between certain bulbs and their CRI:
Characteristics of Common Light Sources
|Light Source||Efficacy (Lumens/Watt)||Average Lamp Life (Hours)||Color Rendering Index|
|Mercury Vapor||25-50||Up to 24,000||15-30|
|High Pressure Sodium||45-110||Up to 24,000||9-70|
|LED||49-100||Up to 100,000||50-90|
|Induction||60-70+||Up to 100,000||80-90+|
Now that you’ve taken a crash course, you are ready to choose some lighting. Depending on the efficiency of the existing lighting, you could reduce energy consumption from 10% to 50% with a payback from two to four years depending on your electric rates.
Here’s a basic target list of savings opportunities to look for:
General Lighting Needs
Look at 4 ft T-12 fluorescent bulbs (bulbs are measured in diameter and 1/8 inch increments so a T-12 is 12/8s or 1.5 inches in diameter and a T-8 is one inch in diameter) and total your operating hours for each light. A 40% reduction in energy consumption can be achieved while maintaining lighting levels.
By the way, it is not legal to dump fluorescents into your garbage bin. They must be properly disposed of according to laws regarding mercury.
Utility Lighting, Down-Lighting & Wall-Washing
Switch from incandescent lights to compact fluorescents – Results in a 70% energy reduction and great savings in maintenance since the typical CFL will last 10 to 15 times longer than an incandescent.
Look to purchase from stores that will take CFLs to recycle when they burn out.
LED Bulbs Replacing Incandescent Bulbs
Results in a 90% energy reduction and an even longer lifespan than CFLs.
Automate when lights are turned off and on based on whether someone is in the room. Classrooms, restrooms, locker rooms, offices, training rooms, copy rooms, conference and meeting rooms, employee lunch and break rooms, and storage and supply rooms are typically suitable locations.
Outdoor Parking Lot Lights
Induction lighting can provide a 40% energy reduction and have an expected life of 100,000 hours for huge maintenance savings.
Outdoor Athletic Field/Tennis Court Lights
Metal halide lights typically used for outdoor applications may eventually be replaced by LED or induction lights. The higher initial investment of purchasing LED and induction lights is recovered quickly through the energy saved and improved lamp life.
Auditorium & Theater Lighting
LED stage lighting products offer improved performance, longer bulb life, requires far less energy to operate, and has a higher degree of control and features to create the ambience appropriate for any concert, dramatic performance or special event.
Opportunities for Daylight Harvesting
The more natural daylight entering a room, the less you need to rely on artificial lighting, thus reducing energy consumption. There are special controls and ballasts needed for this technology. Since schools operate mostly during daylight hours, there can be huge savings.
These are running 24 hours a day. New technologies can cut energy consumption and stop the constant need for bulb replacements. Be sure the exit sign you pick meets all local code requirements. To comply with the Energy Star 2.0 standard, all exit signs manufactured on or after January 1, 2006 must have an input power demand of 5 watts or less per face.
If you have a large number of lights manageable through controls, you could participate in your local utility’s demand response program . With a DR program, you get paid for being able to reduce demand if the utility calls for a power savings event. And you are paid even if no event is called, since you are committing to “stand-by” in case the utility grid is under duress. Typically a minimum of 100 kW load shed is required. In some cases, lighting reduction could be combined with HVAC controls and a standby generator.
After the Audit
A spreadsheet is created to model the current costs of electricity for lighting so a financial benchmark can be determined. The actual electric rates should be used and not averaged since many utilities charge different rates depending on when the electricity is being used. Your utility company should be able to send copies of the past year’s bills if you don’t have them already.
Then, based on your new knowledge of lighting and the lighting data that’s been gathered, your team should be ready to meet and establish a project plan that includes new established lighting levels, desirable design elements and products, maintenance standards, estimated payback, and an installation schedule.
It is critical that after the lighting retrofit installation is done, you go back to test that the controls and light output meet the specifications you desired. It is also important to remember to measure your savings against your previous benchmarked energy use to determine if anticipated savings have indeed been achieved. The energy savings for basic lamp fixtures can be calculated from spec sheets but you will want to confirm the light levels as well. The completed lighting document then gets handed over to the maintenance department with all of the lamp and ballast specifications. Tell maintenance that the specifications listed in the document should not be deviated from. Purchasing different bulbs or ballasts other than the ones specified will impact the energy consumption, foot-candles, CRI and could also reduce the life of the lighting components.
Lighting choices can have a significant impact in lowering your bills and benefiting the environment and can also provide one of the fastest payback items in energy savings for dollars invested. We recommend looking at lighting as part of an overall Energy Efficiency Plan. Use the fast payback on lighting to implement longer-term payback projects that have an even larger long-term value in savings and sustainability. By including efficiency improvements with controls, boilers, variable frequency drives (VFDs), and energy efficient motors, your school will see green savings and sustainable benefits for decades to come. And these benefits will provide you with a great green story to share across multiple channels; social media, website, guest communications and media outlets.
Lighting upgrades are one of the easiest energy upgrades for an organization to make. Good lighting is an essential part of health, safety and student learning and the quick return on investment is just an added bonus. A lighting audit will reveal the best opportunities for the upgrades that will maximize performance and savings. And it doesn’t even have to impact your Capital Expenditure Budget, with financing and shared savings plans available. There simply aren’t many excuses for continuing to tolerate poor lighting in your school, so why should you continue to do so?
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