Efficient Lighting

Lamps - Connecting Devices - Luminaires - Control Systems - Maintenance - Design - Links


Modern luminaire design has resulted in improvements in efficiency compared with older luminaires. Whereas most basic white painted reflectors have a reflectance of about 70%, aluminium reflector reflectance can be up to 95%. Refurbishment of older installations using modern equipment can often result in substantial energy savings in addition to improved visual conditions (e.g. elimination of bright reflections from computer screen). Many modern luminaires contain carefully designed reflector systems to direct the light from the lamps in the required direction. These allow for fewer lamps or luminaires to be used to produce a given illuminance.

It may be possible to improve older, less efficient, luminaires by replacing diffusers or prismatic panels with reflector systems. Alternatively, reflectors may be added to the luminaire, retaining the existing light control components. In some cases this can be accompanied by a reduction in the number of lamps to produce the same illuminance, with consequential saving (energy savings from 20 up to 50% are estimated to be achievable through improvements in reflectors and shielding). Care must be taken, though, since the appearance of the space may well change and a mock-up of a small area to study any changes is usually worthwhile.

Care should also be taken with regard to the light output of luminaires, as these vary considerably. The specifier may unwittingly assume that luminaires produce the same light output when utilising the same number of lamps, but this is generally not the case. Less light output from a luminaire will mean more luminaires will be required to illuminate a given space, thereby the lighting scheme will be less energy efficient. The Light Output Ratio on any given model will vary from one manufacturer to another, therefore checking when deciding on types of models is advisable.