2. Turn it off or turn it down when not in use.
Common sense says lights, air conditioners and heating units should be turned off or down when a building is not in use. But, getting everyone to do their part is sometimes easier said than done. And, there are some innocuous-looking pieces of equipment that use energy that you may not think about, like soft drink machines and computer monitors. One way to get everyone to save energy is to set some guidelines or procedures that everyone can follow.
The Mount Pleasant ISD in East Texas has an energy management program, and from 1995-96 through 1997-98, the district achieved an annual average of $178,000 in cost avoidance, when current costs are compared to consumption prior to implementation of their energy management program. The district’s energy management program focuses on educating people about the importance of turning off devices or lights when not in use.
Lights. The amount and quality of light in buildings affects our health, safety, productivity and comfort. Lighting accounts for approximately 30 percent of school energy bills. Using more light than necessary and leaving lights on when a room is not in use are common mistakes. Turn lights off in unoccupied rooms. The savings are instantaneous.
One way to cut down on lighting costs is to make maximum use of natural lighting. Studies have shown that students learn better in natural light than in artificial light. Use partial lighting and dimmer switches in areas that are suitable for this technique. Teachers should experiment with light levels in classrooms and determine the optimum level for different tasks such as reading and taking notes.
Using energy-efficient bulbs and ballasts can be a quick energy win. New lighting technologies that have developed over the past 10 years can help reduce lighting costs by 30 to 60 percent and, at the same time, enhance lighting quality and reduce environmental impacts. All fluorescent and high-intensity discharge lamps require an auxiliary piece of equipment called a ballast. Ballasts have three main functions. First, they provide the correct starting voltage, because lamps require a higher voltage to start than to operate. Next, they match the line voltage to the operating voltage of the lamp, and finally, they limit the lamp current to prevent immediate destruction. Electronic ballasts improve fluorescent system efficiency by converting the 60 Hz (hertz are a measure of frequency) input frequency to a higher frequency, usually 5,000 to 40,000 Hz. Lamps operating at these higher frequencies produce about the same amount of light, but consume 12 to 25 percent less power. Other advantages include less noise, less weight, virtually no lamp flicker, and some models have dimming capabilities.
MYTH: There is a myth that frequently turning fluorescent lights on and off can cause premature failure of the bulbs and end up costing the school district more for bulbs, labor, etc. The misconception is that an electrical surge occurs when fluorescent lights are switched on, and that this surge consumes much more energy than could ever be saved by turning out the lights.
FACT: The electrical surge is extremely short and insignificant. The wear on the light bulbs is far outweighed by energy savings when the lights are turned off.
Another option to consider is installing motion sensors. The lights will automatically be turned off if no motion is detected in a room or hallway within a stipulated period of time. Leaving lights on unnecessarily for just one hour a day increases electricity costs by 5 to 10 percent per month. For example: let’s say you have a room with two banks of 3 light fixtures. Each fixture has two 40-Watt fluorescent bulbs. In one hour, you’re using 480 Watt-hours or 0.48 kilowatt-hours (kWh). On the other hand, if those lights are turned off just two hours a day, you will save almost 1 kWh and keep almost 1.6 pounds of carbon dioxide out of the air. Instruct cleaning crews to turn lights on only in the room they are cleaning and to turn them off as they leave.
Exit Signs. Every school has a dozen or more very important signs to guide you to the nearest exit in case of a fire or other emergency. The signs are lit to make them visible at night or if the corridor is filled with smoke. They even have back-up battery power so they will operate during an electrical failure.
By law, these signs must operate 24 hours per day, seven days per week all year. It would be a bad idea to install switches on them to turn them off when no one is in school, since one mistake could result in the loss of life. This is one energy-using device that really does need to be on all the time.
A typical exit sign contains two incandescent light bulbs. The bulbs are usually 15 or 20 watts each, adding up to 30 – 40 watts per sign. Although that’s a low wattage, energy consumption adds up, due to the constant operation. For example, 365 days per year times 24 hours per day equals 8,760 hours per year; 8,760 hours times 30 watts is 262,800 watt hours or about 263 kWh (thousand Watt hours). An average cost in Texas for a kWh is 8 cents. At that rate, energy costs for a year of operation will be $21 for the 30W sign and $28 for the 40W sign. That doesn’t seem too bad for a device that could save your life, but costs add up when you consider all the schools in Texas.
There are more than 7,300 campuses across the state. If each school has an average of 10 exit signs, that would mean 70,000 signs are lit 24 hours a day 365 days a year. The total energy bill for emergency exit signs would be $1.5 to $2 million per year. Pollution from generating the electricity for the signs is not included in this cost.
A new type of exit sign is widely available. It uses LED (Light Emitting Diode) arrays that consume 1 Watt, instead of incandescent bulbs that consume 15 to 20 watts each. LED technology reduces the energy use of an exit sign to about 18 kWh per year, for a cost of only $1.44. Each LED exit sign will save $20 or more per year, compared to an incandescent sign, and do the same job of helping to save lives. Another benefit is the long life of LEDs. Incandescent bulbs for exit signs are special long life bulbs that last from 2000 to 5000 hours (regular incandescent bulbs last about 750 hours), but still require replacement about two to four times each year. LED bulbs last 20 to 80 years under normal sign usage! That means a lot less climbing up and down ladders to replace bulbs for maintenance personnel.
Soft Drink and Vending Machine Lights. The lights in soft drink and vending machines help advertise the products inside. Who pays for this advertising? Your school pays for it in the electric bill. The average soft drink machine uses two fluorescent bulbs, which total 80 watts. These bulbs light nearly the entire front of the machine. Add to this the energy required to operate the ballast, a component required to alter the electricity when using fluorescent bulbs. Using a very conservative estimate of only 2 kWh per day usage, a soda machine uses an annual total of 730 kWh just for lights. At an average rate of 10 cents per kWh, this amounts to $73 per year for just one machine!
Through aggressive energy management, the Wylie ISD just east of Dallas reduced their utility budget by 12 percent between April 1, 1999 and April 30, 2000. As part of Wylie ISD’s energy management program, they removed light bulbs out of the soft drink machines and saved about $2,000 per year.
Computer Screen Savers and Monitors. Screen savers prevent screen damage and may provide entertainment. But, while those flying toasters or wacky designs are displayed on your screen, your computer is accessing the CPU and maybe the hard drive, which causes your computer to use energy just as if you were working on a document. Even screen savers that make the screen go blank don’t significantly lower energy use.
The best way to save your screen and save energy at the same time is to turn off your computer when you are not using it. If you will be away for 30 minutes or more, turn everything off – the monitor and the CPU.
The second best way to save your screen and save energy is to turn off your monitor (while leaving the CPU on) if you will be away 15 minutes or more. Your monitor uses the most energy and simply switching if off when not in use will cut your energy use. The CPU will continue to use energy but this is a good compromise. There are even hardware devices that detect keyboard inactivity and automatically cut power to the monitor until someone touches the keyboard.
There is a third way to save energy and your monitor’s screen at the same time. Every computer user should be using this method regardless of whether they are doing the first two. Use the power management features of your computer. Unless your computer is very old, you will have some options for power management (PM). Power management uses software loaded in your computer to cut power to the monitor and make your computer “sleep.”
If you follow these simple guidelines, the Department of Energy claims that your screen and your whole system will last longer.
Heating and cooling equipment. During the day, thermostats should be set at 68 degrees during the heating season and 78 degrees during the cooling season. Set back the thermostats at night and weekends for optimum efficiency. For every degree that the thermostat is turned back, energy is saved. The actual amount will depend upon your use and billing rates. School policies should prohibit leaving windows or doors open while heating and cooling systems are operating. Also, some electric rates are set based on highest peak consumption, called peak load charges. When electricity use spikes at one time, on one day, the district may have to pay a higher rate for months to come. In one district, one day’s peak energy consumption set the rate for the district for the next twelve months. The result was devastating for the district. Using high energy consuming equipment on a staggered cycle can help the district avoid energy use spikes. Some districts have successfully used timers to automatically turn on equipment at timed intervals to avoid spikes.
The Comal ISD in Central Texas implemented an energy conservation program and partially implemented an energy management system. Some of the procedures for the district’s energy conservation program include: setting thermostats at 74-76 degrees for cooling and at 68-72 degrees for heating, turning lights out when rooms are not in use, discontinuing the use of space heaters and unplugging all unnecessary equipment before leaving school.
Comal ISD also installed an automated energy management system in nine of its 16 schools. Comal ISD employs a part-time energy manager to coordinate the district’s energy conservation program and energy management system.
Given Comal ISD’s heated and air-conditioned space of more than 1.3 million square feet and its energy cost of just over $716,000, TSPR found in May 1999 that the Comal ISD used 54 cents per square foot of energy. The EPA estimates the average level of school district energy costs per square foot is $1. Comal ISD’s energy costs are significantly below this benchmark by 46 cents per square foot, saving the district $600,000 annually.
Water heaters. Heating water can use a lot of energy. Equip heaters with timers and temperature settings regulated according to task. The water temperature in lavatories and classrooms should not be set higher than 90 degrees. Water for showers should not be set higher than 100 degrees. It is more efficient to heat water when needed in science labs than to maintain tap water at high temperatures. School kitchens may require hotter temperature settings for safety and health purposes. Finally, do not leave faucets running or dripping. Water is another valuable resource that is costly and must be conserved.
Below is a list of additional resources you may find helpful. Information in the documents and URLs listed below are not necessarily endorsed by this agency, only provided as a resource.
Calculating Energy Costs
(State Energy Conservation Office)
A formula is given to assist energy managers in calculating energy costs using the example of a beverage machine: http://www.window.state.tx.us/tspr/energy/calc.html
Technology Related Energy Conservation
(University of Michigan)
Guide to Green Computing: What You Can Do On and Off Campus: http://www.energymanagement.umich.edu/ems/Green_Computing.html
Energy Conservation Resource Materials
The Lawrence Berkeley National Laboratory Environmental Energy Technologies Division, Building Energy Measurements and Performance Analysis: http://EETD.LBL.gov/EA/Buildings/
Facts and myths about energy management: