Tight facility budgets make low- or no-cost energy expenditure reductions especially important. Many schools can achieve energy savings of up to 25 percent through behavioral and operational changes.
Turning Things Off
The quickest and easiest way to implement load reductions is to ensure that equipment is turned off when it’s not needed. This can be accomplished by recruiting student volunteers or custodial staff as monitors. Students can be enthusiastic ambassadors of a school’s energy-saving goals, and an activity such as creating "turn it off" signs to place above light switches, for example, can be a fun and educational classroom activity.
Computers, printers, and copiers. These should be turned off when they are not in use as well as over weekends and holiday breaks. Smart power strips with built-in occupancy sensors can shut off printers and copiers when no users are present. You can gain significant energy savings by verifying that computer power management settings are enabled on individual computers and monitors, forcing them to enter sleep mode after a specified period of inactivity. The majority of desktop and laptop computers purchased since 2008 are shipped with these settings enabled. Power management settings can cut a computer’s electricity use roughly in half, saving from $25 to $75 annually per computer.
Lights. Lighting strategies are the easiest way to minimize energy consumption without any major expense. Simply turning off lights in unoccupied rooms can save from 8 to 20 percent on lighting energy.
Turning Things Down
Some equipment cannot be turned off entirely, but turning it down to minimum levels when possible can save energy.
HVAC temperature setbacks. If temperature is not controlled by an energy-management system, a programmable thermostat can increase energy savings and enhance comfort by automatically adjusting temperature to preset levels. It can also lower temperatures on weekends and holidays and can save up to $150 on energy costs per year.
Water heaters. Installing insulation on hot-water pipes is a low-cost option that reduces heat loss, allowing for lower water-temperature settings.
Lighting controls. Automatic lighting controls such as occupancy sensors, time controls, photosensor controls, and dimmers save energy and help to reduce maintenance costs. In large restrooms, ceiling-mounted ultrasonic occupancy sensors detect occupants around partitions. For hallways, a recommended strategy is to use a combination of scheduled lighting and dimming plus occupancy sensor controls after hours. Occupancy sensors are also appropriate for storage and faculty rooms.
Pool covers. The annual energy cost of maintaining an indoor pool can exceed $20,000. Pool covers can achieve energy savings of 50 to 70 percent by reducing the need to heat makeup water and by reducing humidity levels so that less energy is needed to ventilate and condition intake air.
Vending machines. Newer, energy-efficient vending machines are available that can greatly reduce operating costs. Whether you are in the middle of your contract or entering a new one, it’s worth a conversation with your vendors to ask them whether they can provide Energy Star–qualified vending machines. Additionally, the use of occupancy sensors can lead to big savings, because they allow vending machines to turn on only when a customer is present or when the compressor must run to maintain the product at the desired temperature. Savings for vending machines equipped with these sensors range from 24 to 76 percent, depending on usage patterns, occupancy in the area, and ambient conditions. Occupancy sensors can be most cost-effective when the machine is located in such a way that people trigger the sensor only when they want to purchase something.
Cleaning and Maintenance
Regularly scheduled maintenance and periodic tune-ups can extend the life of school facility equipment and ensure proper operation.
Building envelope. Upgrades to the building envelope—such as adding insulation or replacing windows—can reduce energy use and improve occupant comfort. All doors and windows should be periodically inspected for leaks. Caulking and weather-stripping leaks help minimize air infiltration and can reduce energy waste.
Air conditioning (AC). Many AC systems use a dampered vent called an economizer to draw in cool outside air and reduce the need for mechanically cooled air. Although economizers can generate energy savings on the order of 2 to 9 percent of building energy use, they are notorious for malfunctioning and their operation is sensitive to temperature setpoints. In fact, a malfunctioning economizer could consume 52 percent more energy than a building with no economizer at all. To ensure that economizers produce savings and don’t waste energy, it’s recommended that you have a licensed technician clean and lubricate movable surfaces and perform functional testing—to identify failed actuators, linkages, and stuck dampers—in conjunction with the air-conditioning system’s annual maintenance.
Fans. Fan blades, bearings, and belts should be inspected at least once a year to prevent failure and maintain efficiency. During the inspection, fan blades should be cleaned, bearings should be checked for adequate lubrication, and belts should be adjusted and changed if needed.
Filters. Air filters should be changed every one to three months. More frequent filter changes may be required for AC units located next to highways or construction sites, or when the economizer cycle is being used.
Leaks. A leak in an rooftop AC unit can cost US$100 per unit per year in wasted energy. On a quarterly basis, cabinet panels and ducts on rooftop HVAC equipment should be checked for leaks. A check should also be made to ensure units are secure, with all screws in place. On an annual basis, inspect all access panels and gaskets, particularly on the supply-air side, where pressure is higher.
Condenser coils. Cleaning the condenser coil is one of the most cost-effective ways to save energy in HVAC systems. A dirty coil that raises condensing temperatures by as little as 10° Fahrenheit can increase power consumption by 10 percent—resulting in about $120 in electricity costs for a 10-ton unit operating 1,000 hours per year. Condenser coils should be checked for debris on a quarterly basis and cleaned at least once a year.
Hot water systems. To maintain optimum efficiency and prevent waste, the burners of gas- or oil-fired water heaters should be tested and adjusted annually. Fixtures should be periodically flushed with hot water to control bacteria growth. Storage-type water heater tanks should be flushed out annually to remove sediments that reduce heat-transfer efficiency.