Lighting design varies significantly for space to space. Each lighting design problem could be addressed in varies ways to suit the lighting objectives. Thus, awareness on energy efficient lighting design concepts is recommended over fixing set rules for energy efficiency lighting design. The three major objectives of a good lighting design are:

1. Health and safety requirements: The design objective should target a well-lit space to work in safety. The design should prevent eye strain, glare, and any harmful radiations.
2. Lighting output and energy use: Based on nature of use, functional requirement, age of user, colour discrimination etc., the lighting conditions are set for the design and associated energy use is maximized.
3. Appearance and comfort: The lighting design is governed by the overall desired appearance of the object or space within it. The objective is expressed based on certain physical parameters like desired mood, atmosphere, safety factor, visual task etc.

Lighting Design Framework – holistic approach

An integrated design approach is necessary for lighting design. This can be done with six elements that influence lighting design. They all need to be considered for best possible solution

• Visual Function- The key components within visual function are:
  • Illuminance – The lighting level at the working desk or a space should be adequate and comfortable. NBC provides the average lux level required for each space category.
  • Uniformity of Illuminance: Uniformity is an integral fundamental for visual performance and discomfort. Variation on illuminance not only hamper the overall appearance of a space but also to the comfort levels and energy consumption.
  • Glare – Glare is an unusual and un intentional excessively bright areas which, directly or indirectly, leads to discomfort visual glare or disability glare
  • Surface colours – The visual aesthetics and appearance of an object or space is resultant of material specification of the target and light source. It is important to first choose the colour type and then select the hue followed by the saturation.
  • Reflectance – The light falling on any surface is partially absorbed and partially reflected based on the material property. This consideration should be included in the lighting design to optimize the fixture requirement and energy consumption.
• Visual Amenity
  • Lighting requirements and aesthetics are the key essence of the lighting design particularly in terms of attractive ness and stimulation.
• Architectural Integration: Integration of lighting could play an important role in overall architectural design. Designer may choose a suitable luminaire like recessed luminaire, suspended luminaire, spot lights, wall mounted, floor standing luminaire, ceiling mounted etc. Each type is for a particular design approach and chosen as per the requirement and installation provisions.
• Energy Efficiency: Lamp technologies, luminaire specifications, and controls are the key approach to ensure energy efficiency in the lighting design. These measures controls the lighting power density on the work plane/ space and operational timings for maximized returns.
• Costs (Capital and Operational) – Capital cost and operational cost are, directly or indirectly, linked to each other. Effort should be made to maximize these two in terms of life cycle cost analysis where an increased capital cost saves the operational expenditure, thereby paying back the additional capital cost in a desired time period.
• Installation Maintenance – The installed lighting should be design to meet the design requirement for a period of time. A gradual decrease of illuminance is observed in all lighting technologies with time because of following reasons:
  • Lamp output reduction (Lamp lumen maintenance factor)
  • Dirt on luminaire (Luminaire maintenance factor)
  •  Dirt on room surfaces (utilization factor)