Every day we are encircled by light either natural or artificial. It is often stated that lighting is as much an art as it is engineering. The art of design for engineers and owners can be condensed to a series of guiding norms.

It is vital to know where the light fixture is placed, at what relative intensities, and in what direction, as it can have major impact not only on vision and visual comfort. In addition, the lighting fixtures we use can also affect the perception of the space.

Lighting impacts satisfaction, visibility, task performance, wellbeing, sales, mood and ambience, aesthetic judgment, and social interaction. It also tells a story about the space, whether a restaurant is selling fast food or a fine dining experience.

Color insight:
Changing CCT, CRI and saturation can have a significant impact on how people, objects and spaces appear. It is crucial to be aware of this.

Focus:
The key principle to be noted is that the human eye is naturally attracted to the brightest area in the field of view. By focusing a higher intensity of light on certain structures in a space, we can make them focal points, directing attention to them, and establish a visual grading. For example, we could promote a key product in display by focusing a higher intensity of light on it.

Understanding of Space:
The pattern of light in a space is known to stimulate a psychological response. For example, positive and bright uniform lighting, with light placed on walls and on the ceiling, can make a space appear visually grander in a lobby. Contrarywise, lower-intensity lighting at a task with a little perimeter lighting can create feelings of intimacy in a fine-dining restaurant.

Aesthetics:
An ornamental, sparkly chandelier in a hotel foyer can convey elegance, for example. Linear suspended luminaires instead of troffers in an office conveys a cool, high-tech look. Similarly, the arrangement of such lighting fixtures sends an aesthetic impression.

Daylighting
Daylighting is the use of windows and skylights to bring daylight into the space. Today’s highly competent windows and advances in lighting design allow efficient use of windows to reduce the need for artificial lighting during daylight hours without causing heating or cooling problems. The dimensions and location of openings is based on the cardinal directions rather than their effect on the street-side appearance of the house, for example. South-facing windows are most beneficial for daylighting and for regulating seasonal temperatures because they allow most winter sunlight into the home but negligible direct sun during the summer, especially when suitably shaded. North-facing openings and windows are also gainful for daylighting because they admit relatively even, natural light, producing little glare and almost no undesirable summer heat gain. Although E-W facing windows provide good daylight penetration in the morning and evening, respectively, they should be limited because they may cause glare, admit a lot of heat during the summer when it is usually not wanted, and contribute little to solar heating during the winter.

Energy-efficient lighting design focuses on processes and materials that improve both quality and efficiency of lighting.

Energy-efficient lighting design principles include the following:

• More light is not necessarily better
• Visual appeal depends on light quality as well as quantity
• Coordinate the amount and quality of light to the performed function
• Fix task lights where needed and reduce ambient light in another place
• Get energy-efficient lighting components, controls, and systems
• Exploit daylighting