Cutting school energy expenditure
As school budgets continue to bite – and Britain becomes the first nation to legislate for cutting carbon emissions – Janey Hewitt finds some timely ways to cut your fuel bills.
With the Government now having set in law a target for reducing carbon emissions, Myton School is blazing a trail towards energy efficiency which could be followed by many others in the years ahead. And not only is the school doing its bit to tackle climate change: the savings being made on its energy bills can be ploughed back into other areas of spending. Myton an 11–18 comprehensive in the south-eastern area of Warwick – began by set up an energy action team to investigate and highlight where energy was being wasted, identifying areas where money and carbon can be saved. The school now asks each department to demonstrate how it is going to make savings, and these strategies will be written into the school development plan. A reduction of only 1°C can lead to financial savings of 6 to 10 per cent on the heating bill, so the energy action team began by looking at heating, and checked the settings of the central heating thermostat as well as the valves on individual radiators. Some rooms recorded excessive temperatures, despite having heating controls fitted, clearly suggesting that a change in behaviour was called for. (The recommended temperatures for heating in schools are 18°C for classrooms and work areas and 15°C for areas such as toilets, halls and corridors.)
Like many other schools, Myton has a number of ‘hut’ buildings. Pupils and staff have commented that the heating in these is not effective, and some huts recorded temperatures well below the recommended level. The team addressed this by recommending new storage heaters in these areas. Modern storage heaters are able to respond more accurately and predictively to outside temperatures and adjust the storage of heat accordingly. Where more immediate heating is required, some models have a built-in convector heater. In rooms where additional heating has been provided it is easy to get into a cycle of ‘too cold, heater on, too hot, heater off, too cold...’ and so on. This is a very inefficient use of such heaters, and schools should be aware of the cost. Typically these are 2kw electric heaters; assuming it is on for, say, a minimum of three hours a day, a single heater would be adding approximately £3 a week to the school’s bill. Multiply this by the number of such heaters in the school, the length of time they are in use, the environmental impact, the comfort and working environment of the users, and it becomes important to consider whether an optimum temperature could be achieved more efficiently.
Myton was using fans in the computer rooms to provide cooling, but if ICT equipment is used more efficiently it reduces the need to cool the room with fans, thus effecting a double saving on energy bills. A further route to explore in these rooms and others with large areas of south-facing windows is the provision of solar film or anti-glare blinds on the windows. This allows the majority of natural light to pass through but reduces glare and solar gain. It is best to use a north-facing room for ICT equipment. Classrooms with full-wall windows are wasteful of energy in at least two respects. If they are not double glazed, the lack of insulation leads to heat loss during the cold weather, and in hot weather the solar gain may lead to the use of fans or even, if there is an unexpected period of warm weather when the heating is on, necessitate opening windows. Replacing the floor-level windows with panels eases the energy loss in these areas (though some might argue that maximum natural light increases effective learning and provides a pleasant learning environment). Further minor ‘housekeeping’ tips to reduce the school’s energy consumption include the following:
• Where curtains or blinds are fitted these should be closed at night to retain heat.
• Doors between areas of differing recommended temperatures should be kept closed as much as possible.
• Windows and exterior doors should be inspected for draughts and draught-proofed. A tiny gap around a door or window frame may have the same effect as having a gap in the wall the size of a large house brick.
• Insulating the central heating pipes means the heat can be focused in those areas where it is most required and also allows more precise control in those areas, assuming that appropriate heating controls are available.
• Radiators should be kept clear of obstruction to enable a proper circulation of warmed air.
• It is important to ensure that the heating is varied according to occupancy, taking into consideration weekends and holiday periods.
• If it is very cold outside, turning the thermostat up higher will not heat the room up more quickly. The result is more likely to be that the room will overheat, subsequently requiring the thermostat to be turned down and thus wasting energy.
Myton’s energy action team next turned its attention to lighting, which accounts for around 25 per cent of energy costs in schools. Substantial savings on the energy bill are possible here, and the team focused on unnecessary lighting and the use of outdated lighting equipment. Replacing the latter can soon pay for itself in terms of efficiency. The team found that a significant amount of energy was wasted by having lights on unnecessarily. This included:
• not switching lights off when there was sufficient daylight
• not switching off upon leaving a room empty
• switching on lights upon entering a room as a kind of reflex, regardless of whether it was necessary
• failure to switch off those lights nearest the window even when this facility was available.
It is important here to dispel the oft-repeated myth that it is more economical to leave a light on than to turn it off and back on. According to the Carbon Trust, a fluorescent tube left on for 15 minutes uses 500 times more energy than is needed to restart it. The school conducted an audit and gave one group of pupils the task of simply checking the lights left on in corridors and other open areas which did not require lighting (as opposed to classrooms, offices, toilets and so on). Their rough data indicated a cost to the school of approximately £20 per week in these limited areas. This may not sound much, but over the months and years, and combined with potential savings in other areas, it would add up considerably. A ‘switch it off’ campaign for energy efficiency may go some way to improving a situation like this and would involve no financial outlay to achieve results.
An additional option, this time involving a capital outlay, is to investigate installing motion sensors in areas such as corridors or toilets, which would turn off lights when not required. Even classrooms and offices may benefit from fitting such devices. Careful checks would have to be carried out in order to ascertain the length of this payback period to determine how viable this would be. Old-fashioned ‘fat’ fluorescent tubes (called T12 tubes) use approximately 10 per cent more energy than more modern ‘thin’ T8 tubes. They are more expensive to buy and they have a shorter lifespan. Continuing to use them is an unnecessary waste of money and contribution to carbon emissions. In most cases the more energy-efficient ‘thin’ tubes will simply slot into the existing light fittings. At the point where the existing stock of ‘fat’ tubes runs out, it should become a priority to investigate replacing them with the better option. Furthermore, it is better to immediately replace fluorescent tubes which show signs of wearing out – typically blackened ends or a delay in lighting up fully – than to wait for them to expire completely, as these will be running increasingly inefficiently, wasting energy and providing inadequate lighting. The energy action team discovered several more ways of cutting the spend on lighting at Myton School. Some were no-cost measures, while others would involve an initial capital outlay which would later be recouped in savings. These steps included a rolling programme of cleaning for light diffusers. If these are dirty, there is more likelihood that extra lights may be switched on unnecessarily where fewer may do the job required. Old diffusers may become discoloured and lead to lower light emission. These should be replaced. Similarly, ensuring that windows are cleaned regularly will also mean less electrical lighting is required, and covering windows with posters or partially shut (sometimes broken) blinds will also lead to increased lighting requirements. For this reason windows should be left uncovered.
Another measure was to rewire those rooms where the electric lighting had not been installed to make use of natural light. Typically these are rooms where, while it may be possible to switch on only some of the lights, it is nevertheless impossible to control those nearest the window independently of those further into the room. A wider behavioural change was called for, though, as full lighting was still often used in the school even in those rooms where partial lighting was possible. More energy than necessary is often used on outdoor floodlighting for sporting activities. The carbon reduction project CRed estimates that replacing high-wattage filament or tungsten halogen lamps with high-pressure sodium or metal halide lighting may lead to savings of up to 70 per cent plus a longer lamp life. The next area Myton’s energy action team looked at was hot water. Their investigations revealed a pressing issue: “Water in room T6 supplies steam rather than hot water!” Regulations give 43°C as the ideal temperature, and the team adjusted the thermostat settings for taps that were too hot – on health & safety grounds as well as to save energy. Other measures that schools might consider to reduce their outlay on hot water include insulating the pipes for both hot water supply and heating. In the case of hot water supply pipes, the longer it takes to run off warm water, the more energy is wasted in heating water which will lie in uninsulated pipework. These pipes should also be insulated. A little planning during refurbishment can also have a big impact, as a system is more efficient when the pipe-runs are shorter between the source of heating and the point of delivery of hot water. And when taps need replacing, remember that taps with timers or spray heads lead to savings on water and energy. We noted earlier that a ‘switch it off’ campaign can go some way to achieving important changes in behaviour among the users of a school, which can help to bring about significant savings of energy. Any electrical equipment left in stand-by mode will continue to consume energy, and not leaving devices on stand-by if at all possible is an important step to take. Indeed, some equipment such as computers and washing machines even continue to use tiny amounts of energy when apparently switched off!
Pulling the plug at the wall may be the only way of reducing the consumption to zero with such equipment. However, the practicalities of the school day in busy classrooms or offices may mean that switching off completely may not be an option. The need for speedy access to such things as computers, photocopiers or printers may make it unreasonable to switch these things off in between users. In this case, it becomes important to ensure that whoever is responsible for buying takes full heed of energy efficiency. Energy wastage due to the use of computer equipment was a particular feature of the campaign at Myton School. The energy action team made several recommendations, as follows. Computer monitors can use up to 70 per cent of the power consumed by the whole system, and should be turned off when not in use. This should become an automatic, reflex action. It may necessitate a change of attitude on the part of users but it can mean important savings. When replacing monitors buy LCD (liquid crystal display) flat-screen monitors. Typically, the energy use for a CRT screen is more than three times as high as that for a flat screen (75 watts in comparison to 22 watts). In the meantime, the relative inefficiency of the older type of monitors makes it even more pressing to switch them off after use. It is important to activate the energy efficiency provision built into computer software. This is not automatically running when a system is set up, and needs to be manually activated to suit the needs of individual users. The power-down provision may usefully be set to 10 minutes for the screen. Microsoft suggests the hard disk power-down should be set to 20 minutes and the system stand-by to 30 minutes. Typically a CRT screen in operating mode consumes 75 watts and in sleep mode only 5 watts. An LCD screen may consume 22 watts in operation and only 3 watts in sleep mode. The potential for savings are clear, then. Reactivating ‘sleeping’ equipment is almost immediate.
Like all electrical equipment, leaving a computer on overnight will simply be a waste of energy. Enabling the power-down features will ameliorate this but power is still wasted. Leaving a monitor on overnight will waste enough power to print 1,000 pages of A4. Screensavers do not save energy; in fact more complex ones may use significant amounts of electricity. Screensavers may be usefully set to blank screen. In rooms where there are large amounts of computer equipment as well as provision for cooling, switching off monitors whenever possible during the day will have a double effect in terms of energy saving: there is the initial saving on the use of the IT equipment and then there is a reduced need to cool the rooms due to the extra heat added by the continual running of the motors.
Thanks to the work of the energy action team, Myton has saved thousands on its bills – money that can be re-invested in areas chosen by the pupils, so they can see and enjoy the tangible benefits of their efforts to save energy. This would be beneficial enough in itself, but with government beginning to set targets for the reduction of carbon emissions, it’s great to see some schools already starting to ‘do their bit’ to fight climate change as well. Taken from Managing Schools Today Issue 16.4
- wigl – what is good leadership?
- wigt – what is good teaching?
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- project-based learning resources
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