Energy Efficiency

A computer left on 24/7 will cost around £25 a year, but if switched OFF at night, weekends and at holiday times, this can be reduced to around £7 a year.

Computers

A computer left on 24/7 will cost around £25 a year, but if switched OFF at night, weekends and at holiday times, this can be reduced to around £7 a year. Now that doesn't sound much BUT If there are 400 computers in your office running 24/7 that is around £10,000 a year. So if we only switched our computers ON during office hours that cost would be around £2,500 a year, saving £7,500 a year! Whilst still doing the things we NEED to do. Incredibly, the amount of energy saved would make nearly 81/2 million cups of coffee (assuming you like coffee).

Lighting

In the UK, lighting consumes around 58,000GWh each year, which amounts to about 20% of all the electricity generated. Switch off all lights when not needed, including tubular fluorescent lamps. Contrary to popular belief that leaving fluorescent lights on saves energy, this type of lamp only uses a few seconds' worth of power when it is turned on.

Lighting costs can be reduced by 20% by only using electric lighting when the space is occupied and when there is insufficient daylight. Always replace or remove fluorescent tubes that are not working. The ballast can still use around 25% of the energy of a lamp and fitting. Significant amounts of energy will still be consumed even when the failed tube is not lit.

Without regular maintenance, light levels can fall by at least 50% in 2-3 years, whilst still consuming the same amount of power. Automatic lighting controls can save 30% on costs. At banks of multiple switches, being able to identify which switch controls which light/s very often prevents ALL the lights being switched on. Label banks of multiple switches. Lighting an office overnight wastes enough energy to heat water for 1000 cups of tea.

This fact is based on a typical office space with 18 x 6ft (1800mm) T8 tubes at 70W each. Ballast increases consumption by 25% so consumption is 87.5W each. Assuming lights are left on when the building is unoccupied for 14 hours (6pm-8am) (14(hours) x 87.5(Watts)) / 1000 x 18(tubes) = 22.05kWh Assume 1 cup of tea requires raising the temperature of 0.25 litres (i.e. 0.25kg) through 70°C (from 20°C to 90°C approx).

Specific heat capacity = 4200 J/ kg/°C Energy requirement = 4200 x 0.25 x 70 = 73,500 J Conversion to kWh = 73,500 / 3,600,000 = .02 kWh

Based on these calculations, then these lights use enough energy to make 1103 cups of tea. In the UK, lighting consumes around 58,000GWh each year, which amounts to about 20% of all the electricity generated. Switch off all lights when not needed, including tubular fluorescent lamps. Contrary to popular belief that leaving fluorescent lights on saves energy, this type of lamp only uses a few seconds' worth of power when it is turned on.

Lighting costs can be reduced by 20% by only using electric lighting when the space is occupied and when there is insufficient daylight. Always replace or remove fluorescent tubes that are not working. The ballast can still use around 25%

Photocopier

A photocopier left on overnight uses enough energy to produce over 1500 copies.

This fact is based on a midvolume copier. In \"sleep\" mode this uses 51W and is on all day. Assume that the office is empty from 6pm to 8am = 14 hours.

Then (51W x 14 hours) / 1000 =0.714kWh In copy mode the machine uses 614W and produces 25 copies a minute (1/60=0.016667 hours).

This is (614 x 0.016667) / 1000 = 0.010233kWh for 25 copies 0.714kWh / 0.010233 = 69.77199 69.7719 x 25(copies) = 1,744 copies could be produced overnight.

Air Conditioning

In a typical office building, airconditioning can double your energy costs.

Lowering the upper set point temperature by just 1oC would reduce the heating bill for a typical office by up to 8% per year, where you are using the AC for heating load.

Equally, increasing the lower set point by just 1oC would reduce your cooling bill for a typical office by up to 8% per year.

Water

Best Practice Dishwasher uses 1.08ltrs per place setting. Best Practice Toilets use 2.6ltrs per flush. The average in the UK is 9ltrs. Best Practice Washing machine uses 7.5ltrs per kg of wash load. Spray taps flow rate 3ltrs per min.

Bath uses 120ltrs - 230ltrs. Auto taps can save 65%. Self closing push taps can save 40%. DEFRA ideal is 120ltrs/person/ day. Code Level 3 Target 105ltrs/p/d.

Gas Heating

Set the thermostat at 19°C costs rise by 8% for every 1oC increase.

Don't heat unused space - storerooms, corridors and areas where there is heavy physical work can be set to lower temperatures. Reduce the heating during holidays, bank holidays and weekends. Keep radiators clear - don't block them with furniture as it reduces the efficiency and output. Thermostats - check they are sited out of drafts, cold and hot spots. Keep windows closed in cold weather.