Lighting and Your Bottom Line

Daylighting and Electric Lighting in Schools

Lighting has always been an important component of educational facilities. In the first half of the 20th century, natural light was the dominant method for illuminating school rooms. Large windows were obviously a key design element. As electric light sources came into use, first incandescent and later, linear fluorescent, meant that school spaces could be adequately lit on inclement days, and classroom hours could be extended earlier, later and into the evening. The use of natural daylighting became less of a consideration.

Given the ever present reality of energy costs and codes, design standards for educational facility design and energy and environmental management, school administrators and planners have developed a new understanding of the psychological and physiological benefits of combining natural and electric light in new and rehabbed school buildings. This is made possible due to recent advances in energy efficient lighting systems, energy efficient windows and skylights and automated control systems that bring the two lighting methods into sync with one another. A properly integrated daylighting system should include:

  • Windows for visual stimulation and occupant “connection” with the outdoors
  • Balanced, glare free daylight, ideally from more than two directions
  • Illuminance levels sufficient for the tasks being performed in each space
  • Lighting system dimming controls and automated shades and baffles to control daylight incursion and to control illuminance levels when computers or AV systems are in use, and to lessen load demand on HVAC systems
  • Sensors and controls that selectively switch off groups of luminaires or lamps within a luminaire based on the daylight contribution

When planning for new construction or renovation, school administrators should consider the cost benefits and paybacks of daylighting systems versus the initial system costs.

  • Enhanced student learning and visual comfort.
  • Reduced electric and HVAC energy consumption.
  • Reduced maintenance costs.

The combination of daylight harvesting and control technologies, combined with low-e glazing and shading systems, results in reduced energy and maintenance costs.

The long term ROI can offset the initial cost of the daylighting system while enhancing student comfort and performance.

Total Cost of Lighting Ownership
The Total Cost of Lighting Ownership (TCOO) of your school lighting system is derived from:

Material Costs
The initial purchase price of the lighting system and components. (Remember that material costs are small compared to the cost of energy to operate the system)
When choosing lamps, consider factors such as: life, color consistency, lumen maintenance, ballast/system efficiency, lighting control options. (occupancy sensors, dimming, daylight sensing, load shedding, etc.)

Energy Costs

The total per annum hours the system operates, multiplied by the local kWh electric rate.
When choosing lamps and ballasts, consider efficiency (lumens per watt), life and lighting control options. Inquire about energy incentives from the local utility and government agencies.


The ongoing cost of maintaining the system: labor, re-lamping, etc.
Consider longer life products (e.g. extended life T5 and T8 fluorescent, ceramic metal halide, LEDs) with superior color stability and lumen maintenance to reduce labor/replacement costs and extend maintenance intervals.


The cost of removal and disposal of lamps, ballasts luminaires and components at end-of-life in an environmentally responsible manner.  Consider longer life products.