Approximately 45% of school's electricity use is consumed out of school hours, when most school buildings are largely unoccupied. ICT and lighting dominate consumption, and also provide the biggest opportunities for savings, particularly reducing consumption from appliances left on 24 hours a day, 7 days a week.
Most appliances today have a standby mode, which historically has been included on appliances to allow them to switch on very quickly or to power a display such as the time, while not actually fully switched on.The most obvious appliance that uses this functionality is the television, which often has a little red light to show it is in ‘standby’ mode. However, other appliances that regularly have a standby mode include anything with a AC/DC charger (e.g laptop, printer, desktop computer), along with common home appliances such as microwaves, dishwashers and ovens.
The older the appliance, the more electricity it is likely to use in standby mode. A TV that is 15 years old could use 12 watts in standby mode, but new European legislation means that new appliances are limited to 1 watt an hour when left in this mode. A new item that adheres to the new 1 watt legislation will cost £1.23 a year to run for doing nothing! While an older TV could cost £15 a year on standby. If you think of all the appliances in your school, this could add up to a significant saving if you encourage everyone to turn off appliances fully, rather than leaving them on standby.
Aim of the investigation
To find out how many lights and appliances are left on or on standby at the end of the school day.
Design a spreadsheet or handwritten results table to record your results. Remember to record the classroom or area of the school where the lights and appliance are located, and the type of appliances you observe. Remember to record whether the appliance is left fully on, or on standby only.
- Go from room to room looking at lights that are around school. In each room, corridor or outdoor area record the number of lights left on, and the number switched off when the room or area is empty.
- Count the number of computers, IT and other electrical equipment left switched on, left on standby or switched off in each room. Don't forget to include monitors, computers, laptops, projectors, whiteboards, speakers, DVD players, televisions, photocopiers, printers, laptop/tablet charging trolleys, and anything else you find. Record your results for each type of appliance, as they have very different levels of energy consumption. For example, an older desktop computer could cost up to £160 if left running 24 hours a day, 365 days a year, while a laptop will cost about £4 and an ipad only £1.
- Why not label things that have been left on or off with sad or smiley faces (or something similar!), to remind classroom users to switch these things off in future.
Data Analysis and Presentation
- Overall percentage of lights left on after school in rooms, corridors and outdoor areas.
- Percentage of lights left on in each department.
- Overall percentage of appliances left switched on across the school.
- Overall percentage of appliances left on standby
- Can you rank the departments in your school from worst to best?
Can you draw some graphs or pie charts to illustrate your results to the rest of the school?
What do your results tell you about pupil and staff behaviour with regard to switching off lights and appliances? Give your evidence for your conclusion. How can you use the information you have learnt to save energy? Can you use your results to persuade the rest of the school to change their habits and switch off to save energy?
Next Steps to save energy
- Behavioural campaigns to remind occupants to switch lights off can be effective, but need constant reminders and feedback to provide lasting benefits. Can you reward the best teachers or departments (perhaps more money for their department budget!)?
- Activate the standby mode on your school computers. Most computers have an in-built standby mode. When the computer is not in use but left on, the computer can power down to a low energy mode. Time to power down can be preset, and usually 15 minutes is appropriate. On average nine out of ten computers do not have the standby mode enabled so it may be worth doing a full audit of the computers around your school. Standby should only be used during lessons and when equipment is being used intermittently. After lessons, equipment should be completely switched off.
- Switch off monitors: This will save over 60% of the energy used by a PC during break times and when it is not required for a particular lesson. Create some reminder posters to get everyone to turn off their monitors between lessons.
- Screen savers don’t save: Screen savers are designed to increase the operating life of the screen – NOT to save energy. If a screen saver is complex and colourful it may actually use more energy than operating in normal working conditions, while inhibiting the power saving features of the computer. Go round your school turning off all screen savers.
- If you have permanently on external security lighting, ask your school management team if they can be switched to PIR lighting which will switch on the lights when movement is detected. Upgrading security lights to LED lighting will improve efficiency, and reduce how often fittings need to be replaced.
Evaluate how you carried out the investigation and what could be improved.
- Repeat this monitoring exercise regularly to check teachers and pupils are improving and more lights and appliances are being switched off across the school.
- Repeat this monitoring exercise at break and lunchtime to check whether lights and appliances are being left on in empty classrooms.
- The use of automatic lighting controls can save as much as 30 to 40% of electricity consumption when compared to manual switching. If you identify problem areas in your school, consider asking your school management team to install occupancy sensors in intermittently occupied spaces such as toilets, changing rooms, and resource rooms. These will switch lights on and off automatically, when people enter and leave the room.