Tips for saving energy in lighting

Easy things to put right

  • People not even knowing where the light switches are
  • Lack of labels on switches controlling shared workspace
  • People thinking it's cheaper to leave lights on. (Find out why they are wrong)
  • Tungsten filament lamps still in use (see alternatives)
  • Excessive light levels for the type of work being done. Guidance levels are
    Type of use
    Lux
    Close detailed work
    1000-2000
    Offices
    400
    Workshops
    300
    Stairs and corridors
    200
    Rest rooms
    100
    Street lighting
    20
    Security lighting
    5
  • Large banks of lights controlled by a single switch.
  • Empty areas lit unnecessarily.
  • Outside lights on fixed timeswitch or manual control.
  • Dirty or discoloured diffusers and shades.
  • Dirty rooflights or other opportunities to use more daylight
  • Artificial lighting used in areas where there is sufficient daylight

Survey tricks and tips

  • Estimate the lighting load by reading the electricity meter at (say) 10 minute intervals first with lights off, then with lights on (see on-line calculation aid)
  • Make a point of examining areas which have had a change of use.
  • Subject to safety considerations, turn off some lights and see if anyone notices.
  • Do an out-of -hours survey to see what lights get left on.

Opportunities

  • Reduce your mains supply voltage (see article)
  • Brief security staff and cleaners to turn off lights when leaving unoccupied areas
  • Improve labelling of switches (combined with a staff awareness and motivation campaign).
  • Replace lamps with more efficient equivalents (take care about colour rendering if important). See lighting efficiency comparison chart
  • Convert mains-frequency fluorescent lights to high frequency fittings.
  • Fit more switches per bank of lights, if wiring permits.
  • Fit automatic lighting controls (carefully chosen to suit the circumstances) especially in infrequently-occupied rooms.
  • Fit more effective reflectors, and remove a proportion of lamps.

Links

(V.V. 21 May 06)

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