Around 20% of all electrical energy generated is used to provide interior and exterior lighting. Paul Davidson, lighting design manager for Ansell Lighting, highlights simple steps to reduce long-term lighting costs.

1  Lamp efficacy

While the importance of using energy-efficient lamps to reduce consumption cannot be overstated, there is also the need to provide good lamp efficacy with high lumen-per-watt values. This can be achieved by using high-efficiency control gear with power consumptions that are within the prescibed limits. At the same time luminaires that have a high light output ratio are able to make best use of the lumens produced by the lamp(s) within the luminaire.

2  Zoning

By controlling the lighting via strategically placed wall switches, luminaires in unoccupied areas can be switched off when not in use or when there is adequate daylight. To further reduce energy usage, the lighting scheme can be designed so that rather than illuminating the whole room to the level required to complete a task, the lighting can instead be directed to where it is required – allowing the surrounding area to be lit with a lower level of illumination.

3  Switches

Timers provide a popular and easy method of reducing energy usage, but do have the disadvantage of having little flexibility. The use of passive infrared occupancy sensors switch lighting on upon detection of a person entering an area. Daylight sensors can typically save up to 40% of energy use each year, enabling the capital and installation costs to be recovered after only a few years. However, this is dependent upon the suitability of the installation and its geographical position.

4 Maintenance

Correct and regular maintenance can also play an important role in reducing energy wastage, as it can be used to determine the ongoing efficiency of a lighting installation. This is due to the fact that over time, there is a marked deterioration in the amount of illumination from a luminaire caused by factors such as lamp lumen depreciation, lamp mortality survival, the aging of the luminaire and the deteriorating state of the environment.

5 Interior surfaces

By using interior surfaces with high reflectance values on the ceiling, walls and floor, along with light colours in the interior décor, fewer numbers of luminaires might be needed as the use of the reflected light from these surfaces, can contribute towards the illumination of the working plane.

Source

Building Sustainable Design